Hitwise provides a look at FriendFeeds clickstream in July, and it shows that Google, Twitter, and Facebook are the biggest sources of traffic.

Twitter is actually a bigger source based on this data, which should make it all the more attractive to Facebook. It would be kind of like Google getting a good portion of its traffic from Yahoo.Facebook intends to let FriendFeed continue operating independently. Its hard to say if Facebooks ownership will significantly contribute to the traffic of FriendFeed.