In this provocative post (mentioned by kgun in another thread) by Rand Fishkin of SEOMoz observes that bloggers are linking less often to articles that interest them. Instead they are Tweeting about them.
SEOmoz | Could Twitter Cannibalize the Web's Link Graph
Do you feel it's tougher than ever, because of Twitter, to get quality links for your site? Will search engines have to start indexing Tweets in a whole new way to stay on top of the trends in information?