Google, Microsoft and Yahoo have agreed on a protocol for sitemaps, so you can now use a single sitemap, that will work for these three search engines. This is really great news. A sitemap will help the search engine to index the whole site, when you give it a structure, so that the search engine doesn’t have to figure out your site all by itself, hence insuring that the site is correctly indexed.
The sitemap is based on Google’s original sitemap format, so the sitemaps already made for Google will now also be indexed by Microsoft and Yahoo. The protocol is offered under Creative Commons Attribution-ShareAlike licence, so it can be used by any search engine. Hopefully this will also push other search engines towards using the protocol.
Sitemaps.org, has been started for this joint agreement. There you’ll find information about the sitemap, the protocol, how to use it and so on. I strongly recommend every webmaster to check this site out, as it will eventually probably change the way spiders work.