To some extent, a lot of the Poser 5 posts are self identifying by having "cloth room," "shaders," etc. in the subject. People that have been around for a while know to be fairly specific when asking a question. Beginners generally aren't going to be asking about the more advanced features of v. 5. A checkbox would be OK but I'm wondering if people wouldn't tend to check whichever version they are using rather than based on features. Someone who went from 4 to 6 might not even know if something was included in 5. There will always be posts that don't interest you, even if you have that version.

"Democracy is a pathetic belief in the collective wisdom of individual ignorance." - H. L. Mencken