Farecast.com announced an expansion of its beta software on which its site is based. Consumers can now get predictions from over 55 cities nationwide. Farecast seems an intriguing idea worth monitoring, but as it is still in beta, we will reserve judgement on its ultimate usefulness until after it has exited the beta process.
A significant part of their expansion is their making their search function available as an RSS feed. You can now use a RSS reader in order to monitor airline fares. This is a valuable service that no other travel site provides.
We cannot yet say we fully endorse this product. But it certainly has features no other travel service has, including our recommendation, Kayak. In the meantime, check the site out, as well as their blog, and make a decision for yourself.