Hey, there are folders in Google Docs! There aren’t actually any folders in my Google Docs, since I haven’t created any. I think I can live without folders there, or in my Gmail. Tags and search seem to do the job pretty well. Having said that, as Gmail becomes my main email, I may see the case for folders there.
I think that folders or categories are useful for newcomers. That’s why there are seven fairly broad categories on this blog (plus Uncategorized). Those categories and their post counts in the sidebar should give a reasonable idea of the content here.