A Google Webmaster Help thread reports the small but yet significant changes made to how Google displays and aggregates the URLs listed in the external link reports within Google Webmaster Tools.
The main changes include:
- Link counts are reduced by a nice percentage
- Ordering of the URLs are now different
- 301 redirected URLs no longer seem to appear in this list
Google confirmed that they handle 301s differently. JohnMu explained:
Redirects are a normal part of the web, but for Webmaster Tools we've currently opted to show only the links that are actually verifiable by visiting the pages directly. It would be nice to show "everything", but at some point we have to draw the line and make sure that the average user can still use it :-).
Forum discussion at Google Webmaster Help.