Tristan Louis compares Technorati, Yahoo, and Google on indexing the blogosphere. Here’s what he concluded:
Yahoo! generally does a better job at indexing the blogosphere than Google does. We know they have been working hard to improve their index and here’s proof that they are getting results
Even if Google is the one with the motto about not doing evil, Yahoo! seems to be the one interested in giving equal opportunity to the little guy: smaller blogs seem to have a better chance of being recognized by Yahoo! than they do of being recognized by Google
While the front page of Google advertises they are currently indexing over 8 billion pages, it is very difficult to find ways to support that claim via the link feature they are offering: this can be seen as confirmation that Google does not tell you about all the links it has in its index.
Sure volume counts but in the case of search indexes, they may count against sites: if one is less likely to appear in Google than it is to appear in Yahoo! and the Google index is much larger than the Yahoo! one, then, if Yahoo! and Google had the same amount of traffic, a single blog could find itself receiving more traffic from Yahoo! than it does from Google. This would be due to the fact that each individual page in Yahoo! has more weight than it does in Google.
The top 100 blogs have other 56 million links in the Yahoo!. That’s a lot of links and clearly shows that links are the currency of the blogging world. It would be interested to get data that would help analyze how much interlinking exists across those sites.