Yahoo! & Deep crawling?

Yahoo! & Deep crawling?: "In Vegas 2004 (Webmaster World conference) Yahoo! talked about the need for creating hierarchies. If you're going to throw in a whack of sitemaps then keep them hierarchical.

Then there's an issue of depth. Yahoo! said that 6 levels deep was probably too deep whereas three was probably fine."

Getting interior pages listed in Yahoo has been a recurring issue that I've noticed over and over again with different clients. This posting from SearchEngineWatch suggests it's possible to achieve a good, deep crawl of a site with many pages, provided the site maps are set up properly.

My impression though, was that Yahoo wants to charge money (alot of money) to crawl your interior urls in their own inclusion program.