Defining Web 2.0

I finally fully understand what web 2.0 means! It's not as if I didn't somewhat understand before, but after reading "The Terrible Twos," I finally feel as though I can give a concrete definition next time someone asks me what library or web 2.0 means. Before reading this articles, I would've likely defined web 2.0 as "the latest in web technology" or something else that is similarly vague. It makes so much sense--of course web 2.0 includes websites that are more interactive and easily edited--and now I can finally admit that I didn't always fully understand what a web 2.0 site was! In the end, though, I'm left wondering what specifically defines a web 2.0 site nowadays, considering this article was published mid 2006. I definitely think interactivity is still a huge factor, but perhaps there are new factors that wouldn't have been around in 2006?