Two days ago we reported, Google Webmaster Tools Link Page Troubles Again. Since then, there has a huge amount of discussion on this topic.
Tons of SEOs and Webmasters were really frustrated that the tool wasn't giving them information. They should keep in mind that this is a relatively new tool that is free and we are lucky to have. :)
In any event, I just checked to see if the tool is now operating correctly and it is. We now can login to Google Webmaster Tools and get to that linkage data without error.
Forum discussion at WebmasterWorld and Google Groups.
