Not just web developers. Web developers on Mac OSX. Textmate's massive lead over everything else is proof positive of that.
Note also the total lack of Visual Studio. It's not even 5%? C'mon. Even just among web developers, ASP.NET is bigger than that.
Curious if git is commonly used in companies over 100 people.
Facebook uses git. Many open source projects with more than 100 contributors do too, of course.
Ah, they do say the people surveyed are at companies with less than 100 employees, so, yeah, there's some selection bias.