The people running Facebook are an ambitious crew; they see Facebook as a successor to Google in many respects. In fact many of the executives used to work at Google, including CTO Bret Taylor, COO Sheryl Sandberg, Advertising VP David Fischer and Communications VP Elliot Schrage, among others.

However as a search property Facebook has, in the past, been almost unusable and no threat to Google or any other search engine. In fact, it has been (so far) a missed opportunity for Facebook partner and investor Microsoft. But Microsoft’s Bing is becoming more prominent on Facebook and the site itself has tried to improve search.

Now the AllFacebook Blog declares that Facebook has declared “war” on Google with an “Open Graph Search Engine” that will create a semantic index of the web (via the Like button) and (eventually) make Facebook search better than Google. Have we thus entered the era of “Facebook SEO”? Should publishers and marketers be optimizing sites for Facebook search and SEO?

Over the past year Facebook has seen growth in search query volumes and has started to approach AOL in terms of overall query volume share, according to comScore. And certainly Facebook search has considerable potential — but that’s still what it is: potential.

AllFacebook shows that non-Facebook sites are now starting to appear and rank in “Facebook” results (as opposed to “Web Results”), as though they were internal Facebook pages — based on how many “Likes” they have:

This is interesting and may begin to create some new user behavior at Facebook, and among publishers/marketers. But Facebook has a long way to go before it can effectively replace Google or any other search engine.

In general the search user experience on Facebook is ambiguous and cluttered. (Marty Weintraub at aimClear details “Facebook Ranking Factors,” which illustrate some of the confusion in Facebook results.) In addition the information available via Facebook search (as opposed to Bing on Facebook) is quite thin right now.

Google, Yahoo and Bing (proper) provide a much more coherent and complete user experience when people really need information.

Has Facebook become an important — even critical — marketing vehicle and promotional tool? Absolutely. Is its search engine going to challenge Google in the near term? Not a chance — at least not without radical change and improvement.

As Danny said to me in an email and a comment on the aimClear blog, “If this is declaring war on Google, Facebook’s starting out by sending a boat against a battle fleet.”