Market watchers will know that bad news usually comes out on Friday afternoon. Bad news for the SEO world came from Yahoo Search on Friday afternoon confirming the death of Yahoo Site Explorer (YSE).

YSE was kind of like an early version of GWT (Google Webmaster Tools) with one very notable difference: YSE provided competitor link information on incoming web links, the only major search engine to reveal that kind of information publicly.

It used to be where you could put any link parameter into the Yahoo! search bar and received the incoming web links to any site.

That little line would yield some valuable insight competitor links. You could build campaigns around the strength of competing websites using the Yahoo metric. That work just got a bit harder and a bit more expensive.

With Yahoo gone what will be a suitable replacement? There’s always SEOMoz and OpenSite Explorer, and Yahoo! is suggesting that the Bing Webmaster Tools console will provide an alternative. However, a free tool like the dying YSE probably won’t emerge.

The announcement also means SEO tools like WEBCEO will lose their usefulness unless Bing comes up with a similar free and accessible link results feature in the Webmaster console. As it stands right now in order to get a comprehensive list of incoming web links for a website you either have to own it, or you have to rely on third party paid tools which are neither wholly accurate nor free.