Yahoo announced today that Site Explorer is not unavailable after the “algorithmic transition to Bing.”

Why should you care? Well, Google and Bing don’t account for all incoming links, only owner-verified ones. Yahoo’s Site Explorer was the last to do so (aside from third-party software like SEOmoz).

Here’s what Google and Bing’s Webmaster Tools cover (via Search Engine Land):

Bing Webmaster Tools:

• Total incoming links over time (currently the previous three weeks)
• Total incoming links to each page on the site (up to a maximum of 20,000 pages on the site)
• List of incoming links and corresponding anchor text (up to a maximum of 20,000 incoming links)

Google Webmaster Tools:

• Total incoming links
• List of most linked pages on the site
• List of domains that link most to the site
• Top anchor text
• Internal links

The closure of Yahoo Site Explorer also goes against the original plans (announced in August 2010):

When Microsoft fully powers the Yahoo! Search back-end globally, expected in 2012, it will be important for webmasters to use Bing Webmaster Center as well. The Bing tool will manage site, webpage and feed submissions. Yahoo! Site Explorer will shift to focus on new features for webmasters that provide richer analysis of the organic search traffic you get from the Yahoo! network and our partner sites.