Do the backlinks in google webmaster tools only update periodically. My tools have been reporting 221 backlinks to my site for 3 weeks despite the fact that I have been actively posting on blogs, forums, and submitting to directories. Is it like the pagerank which is only updated every so often??
Stat from Google Webmaster Tools updates periodically. To check for backlinks why don't you type this in search box: link:yourdomain: faster than in Google tools. And are your new links dofollow? Google only counts dofollow links while many blogs anf forums now are nofollow.
It usually takes 4-8 weeks to see your freshly-built links to show up in google or in yahoo! The speed of the process is directly related to how often Google spiders the sites where you new backlinks reside. Make sure your new backlinks are not on pages with an N/A page rank, as they may take much longer, if ever, to register.
Webmaster tools is 1-2 months behind and snapshot is almost always outdated. @SydneyWhite: No link:domainname is NOT a good method to check backlinks in google. Webmaster tools is more accurate (though almost always outdated)