The Topeka, Kansas, tourism board began investing in paid click campaigns last January, with a budget that sometimes had leftover funds in it. But by 10 or 11 Central Time on Thursday morning, the tourism board's budget for April was gone.

With so many companies launching Facebook fan pages, initiating paid search ad campaigns and developing ecommerce strategies on the site, it's easy to see how Facebook's social network could become the next-generation niche search engine for products and services.