It would be nice to know how many of these are not just online, but fully operational (no 404s, fresh data, etc.). If it's a good proportion of 80+, that's great news for Rails Rumble.
When assembling the data set, anything that was clearly 404'ing or unresponsive was pruned out (one or two might have slipped by, do let us know if that's the case). Fresh data is of course harder to gauge.
Frankly, I was surprised -- and impressed -- that the number was this high. Great stuff.
I wonder how much of that is due to Heroku? Back in the day you'd either spin up a VPS or host it on a spare machine that was doing something else. Now you can throw as many projects as you want up on Heroku and they'll live forever.
This is inspiring for SpawnFest, which is next weekend, and which is the "Erlang Equivalent of Rails Rumble" - http://spawnfest.com.