A few days back [[http://www.ysearchblog.com/archives/000172.html|Yahoo! announced]] that their search index had grown to more than //twice// the size of Google’s index (which, of course, [[http://battellemedia.com/archives/001790.php|Google refuted]]).
So some folks from NCSA went ahead and did a little testing, and the conclusion is that Yahoo’s claims [[http://vburton.ncsa.uiuc.edu/indexsize.html|might be suspicious]]. Are we entering a new world of corporate dishonesty?
To be fair, the NCSA experiment was very very simplistic. I mean, you could do it from your home computer, if you wanted. They just took the standard ispell dictionary file, created around 10,000 random searches consisting of two words and fed them to both Yahoo and Google. Then they compared the size of the result set.
A few points to note — they only compare if the number of results is less than 1000. This can bias the result of their experiment if Google is simply //better// than Yahoo at indexing documents. Its still not a concrete measure of the size of the index itself. Also, their experiments cover regular queries — specialized queries for images, audio/video files, blogs etc are not covered.
But certainly something that Yahoo! is going to note and hopefully respond to in the next few days.