Yep, I've left Facebook several times and Event listings (and the list of who is attending) are always what drags me back.
But that's just a network effect - if those listings were elsewhere, I wouldn't need to return. Someone really needs to make an events app where identity is tied to Twitter / AppDotNet / Email instead. And while you're at it, connect to my Last.FM & Rdio so you can suggest/predict events for me based on my musical taste as well as my interests & friends network.
Well, in your new event app, you'll want to allow people to log in with their Facebook as well, to take advantage of the existing network effect. If you came up with a compelling feature or two, and could get Facebook people to prefer it for their event, it seems you would have a decent chance of traction. Monetization is left as an exercise for the reader.
But that's just a network effect - if those listings were elsewhere, I wouldn't need to return. Someone really needs to make an events app where identity is tied to Twitter / AppDotNet / Email instead. And while you're at it, connect to my Last.FM & Rdio so you can suggest/predict events for me based on my musical taste as well as my interests & friends network.