Are you still doing your blogging exercises? Well here are four (4) search engines I challenge you to add to your blogging bold workout. In addition, you can submit your own blog to some of them.

Blogdigger
Blogdigger is a search engine for RSS and blogs. Blogdigger uses state of the art syndication technologies, such as RSS and Atom, to index blog content and make it available for search. Blogdigger searches thousands of RSS and Atom feeds, and is built-in to many popular News Aggregators, such as FeedDemon and NetNewsWire.

Blogpulse
BlogPulse is an automated trend discovery system for blogs. BlogPulse applies machine-learning and natural-language processing techniques to discover trends in the highly dynamic world of blogs.
Icerocket
IceRocket is an Internet search engine which specializes in real-time search. Based in Dallas, Texas, it launched in 2004 hoping to market itself solely through word of mouth.

Technorati
Technorati Has a Directory of the top 100 as ranked by Technorati Authority.
The Top 100 is updated once per day.