Technorati is an internet search engine that indexes blogs (over 100 million) and tagged social media (over 250 million), and claims to be the world's best blog index. The Technorati claims have been criticized by many and at the same time acknowledged by many as well. An open source based development team with several active developers is what keeps Technorati going despite heavy competition from search engines such as Google and Yahoo.
However, certain aspects of Technorati's model seem very much questionable. For instance, Technorati displays each blog indexed as a part of their website (http://technorati.com/blogs/..) and to a certain extent makes use of others work to increase the number of their pages, and thereby the number of visitors to their pages; improving the website's overall ranking and advertising revenue.
Another fact is that Technorati actually displays each post appearing on publicly visible blogs within their site and display some advertisements based on the content appearing on those particular pages. The advertisements displayed may be purely random, but the content appearing on the page seems to influence at least one such add appearing in many occasions. You can give this a try (make sure to check around 20-30 different blogs/posts instead of making conclusions based on a few).
Whatever the scenario, Technorati does make some amount of money through these advertisements posted on their website (either contextual or not). Also, even members (people who have user accounts) of Technorati can't decide whether or whether not to turn off these adds, and Technorati's making money out of your blog/post is beyond the control of an ordinary individual.
Why this is wrong is a good question. Some bloggers do allow use, re-use or re-distribution of posted content for commercial purposes. But, some don't. There are blog licenses specifically designed to enforce this requirement. The Creative Commons Non-commercial licenses are a good example. These licenses restrict the use of posted content for commercial purposes (read section 4.b of this license which is one of the least restrictive variants).
But, as of today Technorati still does not have a mechanism where they only advertise based on content appearing on blogs that allow use of content for commercial purposes. The correct way to go would be therefore to refrain from advertising on all blogs until they come up with a scheme that is intelligent enough to account for this requirement or pay compensation to affected bloggers. But, sadly Technorati is not doing it in the correct way, and thereby violating the free-right of a blogger to enforce a license that does not allow use of content for commercial purposes.