We're fairly certain that one day there will only be two or three sites on the web. We're not saying the web will look like it did in 1994, but that two or three companies will have a stake in every site you ever visit. We're probably exaggerating, but every time we see a major acquisition/consolidation of competing services, we start to wonder.

Today's big acquisition? Travel site Kayak is reportedly paying $200 million for SideStep. Both companies have web sites that do pretty much the same thing: let you find cheap airline tickets by searching multiple airlines for deals.

VentureBeat reports that Kayak will maintain two separate sites at Kayak.com and SideStep.com, but that SideStep will begin to use Kayak's search technology. What does that mean for people looking for cheap plane tickets, hotels, or rental cars? We're not really sure. While we tend to check out several online travel sites each time we travel we're not really convinced that one has a better track record than another of providing the best deals.

What's your favorite online travel site, and why? Let us know in the comments.