Estimating search engine popularity
First question: why bother, apart from idle curiosity? For a start, I'm interested in knowing how worthwhile it is to do things that help a specific search engine.
Search engines care a lot about their popularity, with the result that you can't really trust anything they say about it. I'm not sure you can trust any other source of information, and to get solid data you probably have to pay money for it.
Besides, I don't care about global search engine popularity; I care about how popular the various search engines are with the sort of people who visit our website.
This has a simple answer: look at your
Referer logs to see how many
people came from each search engine that you can identify. The fly in
the ointment is that this assumes you're equally high in the search
results on each search engine, since people tend to go more to early
To compensate for this, I look to see how we rank on each search engine for the various queries people use. However, it's not enough to just use popular queries, because there may be political factors involved in which search engine gets used. For example, the top search that brings people to WanderingThoughts is a search for a specific Linux error message; how likely are Linux people to use, eg, MSN Search? So I tend to use politically neutral search queries, for example spam-related searches.
This compensation is always going to be an imprecise process, so you are only going to get a rough ballpark estimate of what the popular search engines are. If necessary, you can look only at search queries where you have a roughly equal ranking on all of the search engines. (I don't know if anyone really knows how hits fall off as your search ranking drops.)
Our results are that the only popular search engine is Google. MSN Search has only a smidgen of users (and our search rankings are about the same as in Google), and the others might as well not exist.