If you run one of those sites where parameters can run wild, generating all kinds of multiple URLs for the same content (duplicate content issues anyone?), then this new addition to Webmaster Tools may be able to help.
Under Site Configuration >> Settings, there is something new called "Parameter Handing". Google reports parameters they've found crawling your URLs and suggest how each one should be handled - "ignore" or "don't ignore". You've got a choice to edit their suggested handling, and also to add more parameters to the list.
For some infrastructures, this new tool in the toolkit could be just the solution you need to give googlebot more time to crawl deeper and stop going in circles.
We have a site that Google is removing /redirect.aspx? during the crawl and showing the url as http://www.example.com/ad/1002.htm This is causing a large number of 404's. Suggestions on what parameter add so to add this back into the url?
Well, I just had a look at parameters in webmaster tools for one of our sites and I see that Google reports that it has found parameter "lang" as well as parameter "amp;lang"
Now this is weird as the parameter in URL is actually written in the format "&lang" which should translate into ampersand followed by "lang" parameter. Even worse, it is also reporting that it found parameter "amp%3Blang" (%3B is semicolon).