Help! All my webs drop PR from 4 to 0

[Blacksnow]

and all valuable links gone. What could this be?

 

[temi]

when did this happen to your sites?

 

[LinkHunter]

Are these blogs possibly because there has been a few reports that I've heard for that just recently!! What is your URL if you wouldn't mind sharing?? Maybe we can see what happened!!