Yahoo! has unveiled the new and improved version of Yahoo! Site Explorer. Site Explorer is an invaluable tool, “providing site owners with better visibility into how we [Yahoo!] index their websites and what data we use in our search service”.

As Priyank Garg from Yahoo! Search explains in the release post:

“We launched a new look and feel for Site Explorer http://siteexplorer.search.yahoo.com/new) that provides a more dynamic interface to accommodate future feature roll-outs. The new interface also includes a new Site Summary page to provide statistics for authenticated sites. On top of this, we’re also increasing the number of rules for Dynamic URL Rewriting that you can enter from 3 to 10″.

Google has a similar service for webmasters, known as Google Webmaster Tools. We’ve encouraged all our readers to embrace the Google Webmaster tools for as long as they’ve been available, as they provide great insights for people concerned with their Google organic listing.

Which set of webmaster tools provides the greatest value to site owners? In reality, both services are valuable additions to your SEO efforts. Here’s a quick run-down on the information each set of webmaster tools offers:

With Yahoo! Site Explorer you can:

• Find out which of your site’s web pages are indexed by Yahoo!.
• Discover and track what websites link to your site.
• Know what subdomains from your site are known to Yahoo!.
• Monitor and manage the feeds you have submitted for that site.
• See when the data was last refreshed by our crawlers.
• Resubmit the feed to let us know that it has been updated.
• Download all 1000 results into a tab-separated value (TSV) file at once (and avoid having to page through the results.)
• Learn additional metadata about the URLs from your site in the Yahoo! index, such as language.
• Delete URLs that you don’t want indexed by Yahoo! Search.
• Re-write dynamic URLs to make them easier to index
• Report SPAM.

The Google Webmaster Tools let you:

• Know which of your web pages are indexed in Google
• Uncover which websites are linking to your website (limited view)
• Understand what text is used when linking to your site
• Validate robots.txt files
• Submit and monitor your sites feeds (incl. Subscriber numbers)
• Register and update your websites sitemap
• Understand the top organic queries for your website
• Work out where you feature in the top search results
• Find out when your site was last indexed by the Google crawler
• Understand issues that Google has uncovered on your site
• PLUS…much more

As you can see, both provide impressive levels of site and page level information. If you’re a DIY search engine optimizer, then they should both feature in your regular site monitoring and SEO management.

Ideally, you should track your site in both, but if forced to recommend just one - I still feel that Google provides the better insights of the two (except for inbound link numbers). If you haven’t checked them out yet, I recommend going site exploring now, if no other reason, to marvel at the information available for FREE!