Google & AltaVista and a couplr of others have complex indexing algorithms to follow links and creep down virtual alleys as best they can...those who wish can also 'submit' pages to them, but there are obviously many pages which the owners don't care or want to be indexed...they just want to be accessed by a few. Thus, there is no easy way to count them. I could get software which would allow my home computer to be a 'server' and tell certaing people to log in and look at pictures of my cat, or access my lists of famous left-handed railroad engineers, but AltaVista would be unlikely to find it.

Then you need to decide what constitutes a 'page'....dynamic, static...etc. (I have always thought that a WWW address should be called a 'book', and the various subordinate parts 'pages'.)

So, due to the way it works, it seems that there at LEAST a couple of billion, and maybe several times that many depending on your definition....I personally am willing to accept Dave O's count as of that time, but I think there are now Umpty-leventeen million more.