Ben Essen picked up on this bitly science team post where they’ve taken an interesting look at the half-life of links. We’ve grabbed one of the graphs below. It shows how long links stay hot for over four different sites. The half-life of the links vary quite dramatically across the various networks. It’s interesting to see that on YouTube: these links have a half life of 7.4 hours. On YouTube interest remains for a longer period of time.
From the graph you can see that the team have recorded a half-life of less than 20K seconds (5.5 hours) for Facebook, Twitter and links shared directly. They maintain that they’d ” be very surprised to see any link maintain significant traffic for a lot longer than 60K seconds (16 hours). But for YouTube, we’d be a little surprised to see half-life of less than 5 hours!”
Read more here