Vista - ASP.NET and Search Engine Indexing?

I've seen that ASP.NET supports search-engine optimized (SEO) querystrings such as:

mydomain.com/index.aspx/my_search_term

where "my search term" is the query string that is called by index.aspx.

On the surface, this looks search-engine friendly, but I've NEVER seen a highly-ranked
search engine page using this method.

Now, I don't know if this is because this method isn't successful (Google et al might
treat it as just another query string) or that it just isn't used.

Can anyone share some experience, good or bad, for creating high search engine rankings
using this method?

Thanks so much!

Toni