I enjoying writing my List of Sites that Pass on Link Juice on DP, so here's another quick one: Checkniche http://www.checkniche.com/ You can search for keywords and domains (i.e. .com) and you'll get the most popular on Alexa. Backlink Analyser http://www.seologs.com/link-analysis-tool/backlinks.html Useful tool to check the actual number of backlinks per link to your site. How to track Backlinks http://www.bestblogs.asia/how-to-track-backlinks.php Information tracking backlinks via Comments.