I think FreeRadicals suggestion is good, but it would be better this way:
What's your question about open source or free culture? Be specific.
This way we avoid the word software altogether and cover 4 keywords: free, open, source and culture. Some of these four are usually used in the context of the things we cover here.
I think it should be changed, but "open source" is not the solution, as the accepted meaning of "open source" is "open source code" (i.e. software source code).
We need to broaden this site's scope to more than source code - for instance that we also care about freedom. There is not much room in this field, so a full list of all the stuff that's on topic is ...