A project from MIT's Media Lab that regularly checks what weblogs are linking to, thus tracking information as it flows across the blogosphere. By going to the Blogdex front page you can see which links are most popular on weblogs at the moment. A high ranking on Blogdex is both an indicator that your weblog is getting lots of traffic, and also a guarantee that your weblog will gets lots of traffic, as readers click through from the Blogdex index.

Blogdex was an online resource for understanding hot topics of discussion in the blogosphere.