Last Monday I check Google master tools, my site backlink is 303, last Friday is 325, today is 288 Why this happen ? any idea ? Thanks (UPDATE 15-08-2012) All LINK GONE - Webmaster tools can not see any backlink today
Google's recent Penguin Update only consider the quality back links. so only Your site's back links rate is bouncing.............
However this update does not remove bad backlinks from WMT, so there should be another reason that they all disappeared.
This is may be because: 1. Just like sajithafathima said, google may consider only the quality ones. 2. If you have done any spam blog commenting your comments may have been deleted.
Probably yours link wasn't worth much and Google delete them. Don't worry because it's often case when Google don't show every link. But try to get better quality links and watch out for future.