Visual search is heating up in start-up area. Venturebeat has an article that talks about increased activity in this area. (see http://venturebeat.com/2006/12/11/xcavator-joins-race-in-visual-search/)
The idea behind excavator is something that is intriguing. Many people have talked about it, but it had remained a tough problem even in research community. I am waiting to see how well it works.