About half of bitly clicks on Twitter and Facebook happen within 3 hours

The bitly blog has some interesting tidbits on how long people will pay attention to that link you just shared:

So we looked at the half life of 1,000 popular bitly links and the results were surprisingly similar. The mean half life of a link on twitter is 2.8 hours, on facebook it’s 3.2 hours and via ‘direct’ sources (like email or IM clients) it’s 3.4 hours. So you can expect, on average, an extra 24 minutes of attention if you post on facebook than if you post on twitter.