I generally describe ATP as "a social media website dedicated to gardening."
I think "social media" basically means an interactive website that is more than just forums. We have a lot of extra features that make it interactive, like the database and the acorns and thumbs and all that. It's constantly changing and there's no stuff to see every time you load the homepage. All that interactivity between members is what makes it "social" as far as I can tell.