I'm just wondering if the likes of Facebook and twitter get backlinks from their 'like' and 'tweet' buttons. http://twitter.com/about/resources/tweetbutton has an 'a href' so does this give them significant SEO value. <a href="http://twitter.com/share" class="twitter-share-button" data-count="vertical">Tweet</a><script type="text/javascript" src="http://platform.twitter.com/widgets.js"></script> Code (markup): I think facebook's is a little different but cant access it right now. Do these count as backlinks?
Typically the Facebook links will be within an iframe so they most likely do not get much benefit from that, but the Twitter one would count for them, though the page you are linking to is not likely a page they want to rank for. Regardless of these links, these 2 sites get so many other links that these share links probably do not factor in much. It is also very easy for the search engines to exclude these links.