buckworks - 1:15 am on Aug 8, 2012 (gmt 0)
For years now, Google's link: command has shown only a limited sample of a site's backlinks instead of showing all. I think it's an anti-SEO measure.
Google Webmaster Tools provides a lot more information, but even that's not complete.
It will take more than one research tool if you want extensive information about a site's backlinks.