Technorati- thoughts on week 4

Technorati, the blog search engine seems a bit overwhelming. Then I discovered the tabs that separate what you find into blog posts, blogs, videos, pictures, etc. Do you have to register your blog on technorati, before a technorati search will find it? I can see it as useful if you got a question about a town or travel destination and the patron wanted to see what was being said or what to do in the town with technorati search of the town name. It would also be useful for reviews to pull real actual comments by people about a product such as Chevy Silverado or GE dishwasher. On to week 5.