An answer to this question made me realize just how spread out our programming content is.
- StackOverflow for code questions
- Programmers.SE for whiteboard questions about software development
- CodeReview.SE for code review
- DBA.SE for databases
- PM.SE for project management
- CodeGolf.SE for programming puzzles and "best way to do X" questions
- SQA.SE for questions on quality assurance and testing
- UX.SE for UI design
- Workplace.SE for career questions (still in commitment phase, but career questions are constantly getting closed on P.SE, so there really is no place for them atm)
- Productivity.SE for how to make yourself more productive
- SuperUser for app-related questions
- CSTheory.SE for computer science questions
- Webmasters.SE for webmaster questions
- WebApps.SE for questions about web apps
I can see having some separation between sites, such as
p.se, however I feel there isn't enough special interest groups to validate having some of the other sites.
Personally I find UI questions, code-review questions, programming-related career questions, programming-related productivity questions, code-golf questions, and project management questions interesting, but I am not going to create 6 more accounts and visit 6 more websites to keep up with them. I currently frequent 2 programming-related stackexchange sites (SO and P.SE), and have recently started visiting dba.se a bit more, and feel that keeping up with 3 programming-related sites is about my limit.
One of my biggest frustrations with P.SE is so many interesting questions get closed as off-topic, or get migrated elsewhere, and I don't get a chance to keep up with the answers to them. I used to go to P.SE for all my programmer-related questions, but I can no longer do that.
Perhaps it would be more beneficial to have fewer sites, and to make better use of the tag system to separate broad question categories. We could even have separate moderators for the big tag categories.
Personally for me on SO, I mainly watch broad categories of tags like wpf and mvvm. I definitely don't search tags by stuff like datagrid or file-io. This works out great because I can be happy following questions that are relevant to me, but if I find another question that is interesting, I can keep track of it and follow it without having to leave the site.