I've been frantically trying to get google to index one of our dynamic websites.
Then I got it!
It turns out that using cryptic name/value pairs in the querystrings was causing the problem. Once I started using real words, google went crazy indexing the site.
With a little investigation, it seems that google would index cryptic values, but only if they were short (the limit seems around 6 characters).
An example to demonstrate:
This would not index:
http://www.nomadsworld.com/type.asp?grunt=C19c23C21c17
The same page, new url, has indexed:
http://www.nomadsworld.com/type.asp?...tnam%20hostels
In the past I had no problems with long cryptic values, infact I started to use them so I didn't have the problem of too many name/value pairs. However in recent times google has been either ignoring or dropping those pages.