Stack Overflow
professional and enthusiast programmers
User
8.187.709
Votes
111.976.226
Comments
75.330.837
Questions
15.072.199
Answers
23.502.104
Solved Questions
8.071.056
Unsolved Questions
4.327.422

Server Fault

system and network administrators
User
343.054
Votes
1.713.891
Comments
1.041.051
Questions
253.701
Answers
422.323
Solved Questions
125.863
Unsolved Questions
54.879
Super User
computer enthusiasts and power users
User
633.640
Votes
2.811.162
Comments
1.678.085
Questions
364.970
Answers
541.494
Solved Questions
154.727
Unsolved Questions
117.977

Meta Stack Exchange

meta-discussion of the Stack Exchange family of Q&A websites
User
191.681
Votes
2.283.625
Comments
829.267
Questions
84.833
Answers
125.496
Solved Questions
40.727
Unsolved Questions
10.664

Web Applications

power users of web applications
User
104.759
Votes
243.111
Comments
78.418
Questions
23.308
Answers
33.786
Solved Questions
9.065
Unsolved Questions
3.987
Arqade
passionate videogamers on all platforms
User
113.149
Votes
1.157.442
Comments
395.267
Questions
80.326
Answers
134.272
Solved Questions
50.274
Unsolved Questions
5.901

Webmasters

pro webmasters
User
62.605
Votes
181.220
Comments
115.328
Questions
28.593
Answers
45.229
Solved Questions
12.705
Unsolved Questions
1.586

Seasoned Advice

professional and amateur chefs
User
40.388
Votes
288.215
Comments
110.601
Questions
18.359
Answers
45.441
Solved Questions
9.566
Unsolved Questions
530

Game Development

professional and independent game developers
User
83.953
Votes
385.056
Comments
228.079
Questions
40.437
Answers
63.650
Solved Questions
21.925
Unsolved Questions
5.520

Photography

professional, enthusiast and amateur photographers
User
45.099
Votes
306.911
Comments
138.087
Questions
20.128
Answers
49.651
Solved Questions
10.663
Unsolved Questions
764

Cross Validated

people interested in statistics, machine learning, data analysis, data mining, and data visualization
User
144.994
Votes
717.889
Comments
525.657
Questions
116.044
Answers
110.879
Solved Questions
36.152
Unsolved Questions
46.169

Mathematics

people studying math at any level and professionals in related fields
User
394.934
Votes
5.435.322
Comments
4.587.362
Questions
878.447
Answers
1.234.951
Solved Questions
462.671
Unsolved Questions
196.548
Home Improvement
contractors and serious DIYers
User
50.618
Votes
229.588
Comments
176.044
Questions
34.630
Answers
59.397
Solved Questions
12.942
Unsolved Questions
4.857

Geographic Information Systems

cartographers, geographers and GIS professionals
User
79.570
Votes
538.326
Comments
360.646
Questions
91.581
Answers
108.676
Solved Questions
36.009
Unsolved Questions
19.528

TeX - LaTeX

users of TeX, LaTeX, ConTeXt, and related typesetting systems
User
119.825
Votes
1.805.817
Comments
868.122
Questions
146.897
Answers
192.633
Solved Questions
89.621
Unsolved Questions
10.246

Ask Ubuntu

Ubuntu users and developers
User
516.096
Votes
2.228.606
Comments
1.347.207
Questions
278.975
Answers
362.391
Solved Questions
95.268
Unsolved Questions
91.507

Personal Finance & Money

people who want to be financially literate
User
43.263
Votes
306.844
Comments
125.768
Questions
20.117
Answers
38.941
Solved Questions
9.516
Unsolved Questions
1.226
English Language & Usage
linguists, etymologists, and serious English language enthusiasts
User
186.417
Votes
1.407.702
Comments
851.823
Questions
91.169
Answers
215.667
Solved Questions
45.871
Unsolved Questions
5.541
Stack Apps
apps, scripts, and development with the Stack Exchange API
User
33.009
Votes
24.040
Comments
12.081
Questions
2.356
Answers
2.348
Solved Questions
868
Unsolved Questions
896
User Experience
user experience researchers and experts
User
82.294
Votes
427.650
Comments
158.515
Questions
25.159
Answers
67.146
Solved Questions
12.609
Unsolved Questions
801
Unix & Linux
users of Linux, FreeBSD and other Un*x-like operating systems
User
230.952
Votes
1.273.761
Comments
627.949
Questions
130.141
Answers
195.948
Solved Questions
63.247
Unsolved Questions
30.485

WordPress Development

WordPress developers and administrators
User
98.758
Votes
329.887
Comments
372.251
Questions
83.773
Answers
105.606
Solved Questions
40.357
Unsolved Questions
24.054

Theoretical Computer Science

theoretical computer scientists and researchers in related fields
User
31.741
Votes
205.388
Comments
73.942
Questions
9.134
Answers
13.457
Solved Questions
4.272
Unsolved Questions
2.211

Ask Different

power users of Apple hardware and software
User
184.573
Votes
649.950
Comments
336.980
Questions
88.174
Answers
130.984
Solved Questions
33.303
Unsolved Questions
27.216

Role-playing Games

gamemasters and players of tabletop, paper-and-pencil role-playing games
User
27.801
Votes
725.089
Comments
150.786
Questions
24.813
Answers
60.154
Solved Questions
17.063
Unsolved Questions
89

Bicycles

people who build and repair bicycles, people who train cycling, or commute on bicycles
User
24.629
Votes
168.103
Comments
92.515
Questions
10.907
Answers
27.096
Solved Questions
5.757
Unsolved Questions
310

Software Engineering

professionals, academics, and students working within the systems development life cycle
User
239.819
Votes
1.964.762
Comments
697.333
Questions
47.547
Answers
144.252
Solved Questions
27.857
Unsolved Questions
2.640
Electrical Engineering
electronics and electrical engineering professionals, students, and enthusiasts
User
117.449
Votes
773.155
Comments
741.278
Questions
92.252
Answers
163.456
Solved Questions
47.126
Unsolved Questions
9.208
Android Enthusiasts
enthusiasts and power users of the Android operating system
User
151.786
Votes
287.306
Comments
204.095
Questions
46.726
Answers
56.508
Solved Questions
13.374
Unsolved Questions
19.891
Physics
active researchers, academics and students of physics
User
120.617
Votes
984.171
Comments
703.473
Questions
110.647
Answers
161.338
Solved Questions
47.113
Unsolved Questions
22.825
Information Security
information security professionals
User
127.538
Votes
742.851
Comments
281.403
Questions
43.817
Answers
81.640
Solved Questions
20.900
Unsolved Questions
3.593

Graphic Design

Graphic Design professionals, students, and enthusiasts
User
74.875
Votes
229.898
Comments
118.897
Questions
23.157
Answers
42.273
Solved Questions
10.617
Unsolved Questions
2.033

Database Administrators

database professionals who wish to improve their database skills and learn from others in the community
User
113.143
Votes
432.121
Comments
272.870
Questions
61.303
Answers
82.749
Solved Questions
29.583
Unsolved Questions
11.538
Science Fiction & Fantasy
science fiction and fantasy enthusiasts
User
66.725
Votes
1.394.503
Comments
394.602
Questions
44.514
Answers
86.560
Solved Questions
26.408
Unsolved Questions
2.911
Code Review
peer programmer code reviews
User
132.505
Votes
569.120
Comments
274.172
Questions
49.654
Answers
79.530
Solved Questions
28.819
Unsolved Questions
4.838
Programming Puzzles & Code Golf
programming puzzle enthusiasts and code golfers
User
58.300
Votes
697.585
Comments
276.598
Questions
9.019
Answers
109.701
Solved Questions
4.852
Unsolved Questions
80

Quantitative Finance

finance professionals and academics
User
19.911
Votes
74.869
Comments
42.307
Questions
9.947
Answers
13.430
Solved Questions
3.883
Unsolved Questions
2.267

Skeptics

scientific skepticism
User
29.215
Votes
328.051
Comments
122.091
Questions
8.222
Answers
10.293
Solved Questions
4.035
Unsolved Questions
1.077

Drupal Answers

Drupal developers and administrators
User
48.981
Votes
383.008
Comments
256.413
Questions
74.842
Answers
96.054
Solved Questions
33.917
Unsolved Questions
22.902
Motor Vehicle Maintenance & Repair
mechanics and DIY enthusiast owners of cars, trucks, and motorcycles
User
23.332
Votes
137.233
Comments
71.500
Questions
14.696
Answers
23.755
Solved Questions
5.801
Unsolved Questions
1.927

SharePoint

SharePoint enthusiasts
User
46.476
Votes
238.405
Comments
216.215
Questions
77.798
Answers
99.085
Solved Questions
30.613
Unsolved Questions
26.045

Music: Practice & Theory

musicians, students, and enthusiasts
User
29.474
Votes
183.377
Comments
80.279
Questions
11.907
Answers
31.922
Solved Questions
6.143
Unsolved Questions
324
Mi Yodeya
those who base their lives on Jewish law and tradition and anyone interested in learning more
User
8.931
Votes
275.476
Comments
202.315
Questions
23.931
Answers
37.982
Solved Questions
8.232
Unsolved Questions
3.717

Japanese Language

students, teachers, and linguists wanting to discuss the finer points of the Japanese language
User
15.802
Votes
176.902
Comments
67.688
Questions
14.600
Answers
23.228
Solved Questions
10.380
Unsolved Questions
92

Philosophy

those interested in the study of the fundamental nature of knowledge, reality, and existence
User
21.616
Votes
104.890
Comments
94.908
Questions
9.242
Answers
21.711
Solved Questions
3.560
Unsolved Questions
895
Travel
road warriors and seasoned travelers
User
48.581
Votes
545.375
Comments
201.836
Questions
27.218
Answers
45.548
Solved Questions
12.137
Unsolved Questions
143
Cryptography
software developers, mathematicians and others interested in cryptography
User
39.214
Votes
141.678
Comments
88.218
Questions
14.610
Answers
18.980
Solved Questions
7.434
Unsolved Questions
1.839
Signal Processing
practitioners of the art and science of signal, image and video processing
User
24.327
Votes
71.720
Comments
69.757
Questions
13.743
Answers
17.199
Solved Questions
5.989
Unsolved Questions
3.149
Christianity
committed Christians, experts in Christianity and those interested in learning more
User
18.991
Votes
213.656
Comments
119.938
Questions
9.628
Answers
22.680
Solved Questions
4.986
Unsolved Questions
234

Bitcoin

Bitcoin crypto-currency enthusiasts
User
45.751
Votes
127.401
Comments
57.926
Questions
17.602
Answers
23.857
Solved Questions
6.923
Unsolved Questions
3.064

Movies & TV

movie and tv enthusiasts
User
39.484
Votes
379.160
Comments
103.988
Questions
18.083
Answers
27.990
Solved Questions
10.910
Unsolved Questions
1.562

Biology

biology researchers, academics, and students
User
26.866
Votes
178.591
Comments
97.020
Questions
18.250
Answers
21.273
Solved Questions
8.333
Unsolved Questions
3.441
Mathematica
users of Wolfram Mathematica
User
36.323
Votes
623.415
Comments
354.561
Questions
48.452
Answers
71.230
Solved Questions
26.233
Unsolved Questions
5.502
Academia
academics and those enrolled in higher education
User
64.132
Votes
728.625
Comments
213.116
Questions
21.513
Answers
50.270
Solved Questions
9.580
Unsolved Questions
758
Computer Science
students, researchers and practitioners of computer science
User
64.773
Votes
201.637
Comments
138.048
Questions
23.152
Answers
28.040
Solved Questions
10.697
Unsolved Questions
4.229

The Workplace

members of the workforce navigating the professional setting
User
56.415
Votes
841.974
Comments
222.532
Questions
17.241
Answers
55.211
Solved Questions
8.577
Unsolved Questions
4

Chemistry

scientists, academics, teachers and students
User
35.352
Votes
244.669
Comments
121.783
Questions
24.466
Answers
28.532
Solved Questions
10.016
Unsolved Questions
4.431
Raspberry Pi
users and developers of hardware and software for Raspberry Pi
User
62.381
Votes
121.373
Comments
99.533
Questions
20.961
Answers
27.688
Solved Questions
7.488
Unsolved Questions
5.914
Salesforce
Salesforce administrators, implementation experts, developers and anybody in-between
User
34.667
Votes
308.245
Comments
262.156
Questions
70.583
Answers
83.279
Solved Questions
30.972
Unsolved Questions
20.294
ExpressionEngine® Answers
administrators, end users, developers and designers for ExpressionEngine® CMS
User
5.441
Votes
38.138
Comments
33.031
Questions
11.946
Answers
15.302
Solved Questions
5.721
Unsolved Questions
2.519
Anime & Manga
anime and manga fans
User
19.387
Votes
129.027
Comments
45.586
Questions
8.679
Answers
12.840
Solved Questions
4.799
Unsolved Questions
1.013

Magento

users of the Magento e-Commerce platform
User
43.767
Votes
240.991
Comments
247.571
Questions
68.400
Answers
80.105
Solved Questions
25.988
Unsolved Questions
24.161

English Language Learners

speakers of other languages learning English
User
50.243
Votes
352.346
Comments
246.297
Questions
45.341
Answers
74.790
Solved Questions
23.195
Unsolved Questions
3.404

Network Engineering

network engineers
User
31.567
Votes
62.166
Comments
65.651
Questions
10.102
Answers
15.467
Solved Questions
5.285
Unsolved Questions
1.140

Blender

people who use Blender to create 3D graphics, animations, or games
User
35.035
Votes
194.303
Comments
139.475
Questions
35.467
Answers
35.222
Solved Questions
14.761
Unsolved Questions
9.793

MathOverflow

professional mathematicians
User
74.900
Votes
1.523.004
Comments
592.057
Questions
88.024
Answers
128.055
Solved Questions
41.152
Unsolved Questions
21.676

Stack Overflow em Português

programadores profissionais e entusiastas
User
72.142
Votes
511.070
Comments
449.893
Questions
90.194
Answers
110.647
Solved Questions
46.928
Unsolved Questions
22.290

Aviation

aircraft pilots, mechanics, and enthusiasts
User
20.485
Votes
267.434
Comments
88.721
Questions
10.804
Answers
20.885
Solved Questions
6.300
Unsolved Questions
354

Software Recommendations

people seeking specific software recommendations
User
28.439
Votes
76.168
Comments
46.901
Questions
14.142
Answers
13.852
Solved Questions
3.063
Unsolved Questions
6.601

Arduino

developers of open-source hardware and software that is compatible with Arduino
User
30.170
Votes
58.276
Comments
76.945
Questions
13.273
Answers
18.712
Solved Questions
5.522
Unsolved Questions
2.637

Data Science

Data science professionals, Machine Learning specialists, and those interested in learning more about the field
User
33.373
Votes
43.964
Comments
22.993
Questions
7.273
Answers
8.978
Solved Questions
2.580
Unsolved Questions
2.073
Puzzling
those who create, solve, and study puzzles
User
31.493
Votes
346.085
Comments
142.208
Questions
10.968
Answers
29.833
Solved Questions
9.180
Unsolved Questions
66
Worldbuilding
writers/artists using science, geography and culture to construct imaginary worlds and settings
User
37.132
Votes
560.078
Comments
257.084
Questions
14.347
Answers
69.722
Solved Questions
7.951
Unsolved Questions
5

Emacs

those using, extending or developing Emacs
User
12.583
Votes
84.335
Comments
47.428
Questions
12.347
Answers
14.452
Solved Questions
6.590
Unsolved Questions
2.843
Stack Overflow на русском
программистов
User
99.903
Votes
695.788
Comments
909.217
Questions
182.691
Answers
220.281
Solved Questions
90.799
Unsolved Questions
42.613
Law
legal professionals, students, and others with experience or interest in law
User
11.265
Votes
47.723
Comments
35.306
Questions
7.898
Answers
9.782
Solved Questions
2.922
Unsolved Questions
1.422

Stack Overflow en español

programadores y profesionales de la informática
User
61.479
Votes
140.317
Comments
203.371
Questions
42.593
Answers
52.232
Solved Questions
18.957
Unsolved Questions
14.414

Ethereum

users of Ethereum, the decentralized application platform and smart contract enabled blockchain
User
22.843
Votes
70.875
Comments
31.797
Questions
12.587
Answers
13.616
Solved Questions
5.028
Unsolved Questions
3.439