SearchMonkey - If you've marked up your site with SearchMonkey code or provided a feed with a SearchMonkey template, you'll be able to use Site Explorer see what Yahoo! has indexed.
Yahoo! Search Key Terms - Launched last November into BOSS, Key Terms allows developers to develop refinement terms for their search services. Yahoo! is now providing information on Key Terms used on websites through Site Explorer
Delicious - Information about your site's pages being submitted to the social bookmarking site will now appear in Yahoo! Site Explorer.
Yahoo! has also updated the dashboard for Site Explorer as well as the backend logic for SearchMonkey feeds. Developers can now validate small test feeds quicker.
Have you checked out the updated Yahoo! Site Explorer? Let us know what you think by leaving a comment.