Ev Williams who helped start Twitter says he continues to be frustrated that Facebook won't let users share data more easily. For instance, you can automatically have your tweets become Facebook updates but you cannot make your updates become tweets. You also can't check through Twitter which Facebook friends are tweeting. This issue follows the recent tiff between Facebook and Google where Google got sick of Facebook not letting users share their data in any platform other than Facebook. Basically, it's a one way street. Williams says that he understands that Facebook's position is that it's "social graph" is the core product of the company but it's still irksome. So it really comes down to whether Facebook is big enough that it doesn't have to play nicely with others.