According to Jimmy Wales blog, Wikia Search has shut on March 31, 2009. Wikia had raised funds from well-known personalities and it was being promoted as ‘open source search’. It did not take off 🙁
The alpha version was released in Jan 2008. According to an article on Cnet, Wikia was getting merely 10,000 unique visitors a month for the past six months. Sounds very low 🙁
I personally believe it is difficult (rather impossible) for anyone to take on Google Search. Having said that, I must mention we are seeing a lot more referrals from Yahoo and Live.com over the past 2 months.