It may seem like a basic question, but Ted Patrick just posted a nice deconstruction titled What is Flex? on his blog. Definitely a nice permalink for this site, as the nature of FlexFM makes it a likely first contact with Flex.
He concludes by stating (with the self admitted bias of an Adobe Evangelist) that Flex is, “A development platform that is revolutionizing how the world writes and deploys software!”
A bold statement? Perhaps. A true statement? Could be. You be the judge.