I can say anecdotally this applies to me. I use ASP.NET and C# heavily and am a daily user on StackOverflow, but I rarely find myself needing to ask a question there. I usually just find an answer to what I need and vote and favorite accordingly. It's become more of a repository of information for me than when it started out.
Some drop in ASP.Net/C# popularity wouldn't surprise me either though.
This is a problem I run into. As a more junior developer, nearly all of my questions I haven't been able to answer with research have already been answered on stackoverflow. Employers want me to have tons of points, but I don't usually have to ask any questions.
Your employers actually track your StackOverflow karma??
Re:Programming Trends on StackOverflow
by mattmanser on Friday July 05, 2013 @11:56AM
(#5995410)
In the lifetime of the site c# 3 came out with a lot of new programming paradigms, ASP.Net MVC has come out, Silverlight has come and gone, WPF has gone from being something no-one uses to something a lot of people do and windows phone and now windows 8 have come out.
Contrast that to Java which had Android, which people don't seem to bother tagging as Java? And that's about it I think? And Java grew and stabilized, so it really is probably just down to their initial users consisted overwhelmingly of .Net developers.
To put it another way, as the site matures, more questions about x will tend to correlate to the inverse of x's formal repositories of knowledge.
A user who finds an answer to their ASP.NET question on StackOverflow, doesn't ask a new question.