A thread on Search Engine Watch entitled OpenRank - An Open Source WWW Index explains a new project by the user randfish. It is called Open Rank - the idea is that they would build a large index all webpages (I think they are hoping for at least 1.5-2 billion pages indexed). This would not be a search engine, instead, it would be built primarily for SEO's to freely have access to the index.

At the moment we are too reliant on search engines, say Yahoo and MSN stopped giving useful backlink information (like Google has), this would be a serious problem for SEO's when accessing links quality and general link building etc. With OpenRank there would be no worries because you wouldn't need to reply to search engines to supply SEO's with this information.

But it's not just backlinks you could find, Imagine all the functions that Google could have to help SEO's if they wanted to. Personally I think this idea has a lot of potential, the only barrier is indexing the entire web (which is a big one!). I hope they succeed.