Airfare prediction Web site Farecast.com has debuted a service that lets customers protect the lowest airfare for their trip without buying a ticket. Fare Guard comes six months after the launch of the meta-search travel site to the national market, and it illustrates Farecast's confidence in its predictions for airfare. Transparency and openness of information is the next evolution for online travel sites, said Mike Fridgen, vice president of product and marketing at Farecast, Seattle. Consumers want to know more information, and now it's about that next level of transparency and showing all of the information about the price. Farecast works like a stock prediction. It measures recent fares on any mix of dates and times on hundreds of airlines and combines this with historical fare rates and trends to speculate on the cost of upcoming fares. The prediction shows whether the lowest fares on a specific trip ar