For those not aware, Roll20 is part of the Firebase beta for our server needs (not the actual storage of campaign data, but the syncing of elements / hosting). We're pretty lucky to be working with these fellows and they've been nothing short of great.
Anywho, check out this article which heavily features them:
<a href="http://arstechnica.com/business/2012/05/say-hello-to-the-real-real-time-web/" rel="nofollow">http://arstechnica.com/business/2012/05/say-hello-to-the-real-real-time-web/</a>