WebmasterWorld members are already beginning to notice some issues with the Google SERPs this month, though it has only just begun.
In one instance, a very highly targeted one-page website which used to perform well for short and long tail terms lost all traffic in the short and long tail. This month, the webmaster reports that short tail searches are starting to creep back up but long tail results are nowhere to be found.
Many people keep alluding to a June 4th disaster with the -950 penalty. They're also losing substantial traffic (see this thread). This month, only few admit that they've recovered.
Another forum member admits that he has been seeing a jump in rankings -- from page 1 to page 6. He's worried that his hard work has gone to waste.
Forum discussion continues at WebmasterWorld.