"Glync is a Firefox extension which adds historical graphs to the External Links page in Google Webmaster Tools. This means that you can track your link growth over time."

http://www.thegooglecache.com/glync/

(found via http://searchengineland.com/glync-adds-link-timeline-to-google-webmaster-tools-15388.php)

Thanks for the mention – I just couldn't wait any longer for google to come out with the functionality, so I made it myself :)

How this tool access our data? Does it save our passwords in its own database? :-/