The topic is discussed at length in an article by FastCompany, where a pair of authors (with the help of an NYU intern) breaks down a list of the most probably blog search “engines”, and lists some pros and cons of each of them, including their methodology for how each search engine “ranks” their searches. For example Technorati ranks primarily according to thenumber of in-bound links a given post has, although it does have problems recognizing the number of links (it can underestimate it).
Their summary remarks suggest that…
There is obviously no perfect ranking system on the Internet–either for blogs or for web sites in general– and there probably never will be. Our recommendation is that PubSub try to focus their results on real blogs; too many of their results are commercial sites or blog utilities. Technorati needs to become more accurate in their counts of links. Bloglines and Feedster could be substantially improved if they took the next step and separated the blogs into categories. If your goal is to find the most influential bloggers, in a given category or overall, you’re best off using Technorati.
No clear winner is announced in terms of best ovreall search, but its an interesting article because I’ve rarely seen anyone breakdown these search engines this way. Its also interesting that although the discussion starts off with trying to understand blog search and the accuracy thereof, the data is really about how each blog search ranks its highest or influential blogs — which isn’t the same thing.
What would have been helpful is an analysis of how each search engine does in terms of actual search terms, trying to understand what the results mean in terms of relevance, freshness, and authority (the latter technorati does seem to do well enough), and perhaps ranking on their ability to find results for that.
Still, its a good start to encourage some conversation as how these search engines rank blog posts. “Link tracking, in-linking, feed subscriptions, tags, viewer ratings” are all one form of metric or another, and I think its important that bloggers know how their own blogs are doing — and question how they appear on search engines. It may not be the most important way they get traffic, but for many, its a significant one.
