Blogs thrive on users coming, spending time reading and leaving comments. Technorati only advertises on its home page, however, and is not moving towards advertising on blogs (Adsense does though). You can be a sponsored listing, but you should pass on the graphic ads unless you know something that I don't. Here are some interesting facts on blog readers from a 2005 ComScore Media Matrix report.
Compared to the average Internet user, blog readers are significantly more likely to live in wealthier households, be younger and connect to the Web via high speed connections.
Blog readers also visit nearly twice as many web pages as the Internet average, and they are much more likely to shop online.
If you can find some way to get on the blogs (Adsense wins again), and skip the blog search engine itself you may have a winning approach. If you do want the graphics ads -- they are keyword based (contextual) and come up during searches, mainly on the top right and on the right of the page -- note that Technorati announced very grandly in July that it is are downplaying its ads. Its service is not a cost per click program, but a "buy advert space" paradigm. The ad prices are actually rumored to be quite cheap, maybe $15 a month for some keywords using their three-in-one graphic, which allows three different adverts to be placed on one spot (tristital).
Technorati for Searchers
The Technorati search allows searching by date combined with authority only and does not allow searching by relevance. Authority is how many other blogs link to it. For my searches (my first search was flow cytometry) I did not find relevant listings on what I wanted when presented with the results on my keywords with high authority. The first few listings were not very good (to put it mildly) and I was served unrelated content, mostly personal moans on how good or how bad life has been to the bloggers. Lest it seem that I am Technorati bashing, the same search in Bloglines gave relevant results (sorting by date was an option, not default) even for some pretty technical terms such as "flow cytometry" and "Semantic Web Design."
I ended up using Technorati for a week, benchmarking using Bloglines, Feedster, and Yahoo's Blog search. The only search engine worse than Technorati in returning relevant results was Yahoo Blog search results. Several times while Feedster, Bloglines and even Technorati gave results, Yahoo Blog search claimed not to find any results for "Flow Cytometry."
My experiences with Technorati make me believe that it is basically built around the blogging community and not around searchers per se. It is not a very good place to search for serious content, but if you want to add comments to a large amount of posts which are created by real people, you are home.
Search Engine News 
