Linktree offers a no-cost tool that will tell you, site by site, who is linking to your competitors but is NOT linking to you. Simply enter the URLs of at least five competitors, enter your URL, and voila! Out pops a list of those websites that are excluding you from the linking party, plus links to the pages where your competitors’ links appear. You can then use your common sense or other competitive recon tools to decide whether or not it’s worth your time to approach those sites, hat in hand, requesting that your site be added to their link collections. This service is different from other link popularity comparison tools because it allows you to exclude your own site and thereby easily create a list of target prospects that aren’t linking to you.