Technorati is more than just a directory; it allows you to search content for all its listed blogs based on specified subject matter. It also has a hierarchy and assigns a ranking to each blog in its network and a free service which lets you list all your blogs and update the listing automatically, or manually as often as you want. Technorati tracks over 50 million blogs, making it the largest blog listing site in the known universe.

Blog Catalog is actually a social networking site and a blog directory. You can create a profile and make friends on the site; and when you place new content on your blog, you can quickly notify your contacts about it. Blogs can be added to the site, but must be approved before they go ‘live’ in the directory.