I see 6 cases of "Microsoft .NET Framework" in my add/remove programs list, taking up about 600 MB of disk space (on 250 GB, that's less than 1%, practically nothing). The usage is showing "rarely" for all of these. This usage information is unreliable. I've used GIMP actively in the past 2 weeks and still shows up as "rarely" for both it and the related GTK. About 2 years ago, I didn't have any of this .NET Framework stuff. I'm only wondering what it's used for and if it can otherwise be uninstalled.
Edit: forgot the "uninstall" in subject line, for making it clearer.
To grossly oversimplify, it's a package of common support software that can be used by programs so that they don't all have to re-write the same software over and over again. More specifically, it's aimed at users of Microsoft's newer versions of programming languages like C#, Visual Basic .NET and others. The .NET framework provides a broad array of functionality that can be used by programs written in those languages to perform common tasks, most commonly things that involve interacting with Windows itself. http://ask-leo.com/what_is_the_net_framework_and_do_i_n...
Oh, so .NET is to C#, Visual Basic .NET, etc. as msvcr.dll is to C? Well, in that case, then it's definitely worth keeping (or you'll just get errors and the program won't run). Oh well, I wonder why even 2 years ago I didn't have these.