An FMA (Flexible Messaging Area) is a Flash banner or an image that is displayed on the Home page of a site for higlighting a product or event, or just to give the visitors a brief overview of the main aim of the site.
Most sites use a full flash banner that runs the full width of the displayed area of the home page of the site. Some developers cleverly design a JPEG or PNG image to convey the message as well.
A proper definition of FMA is given by Tony Lopez who worked for Macromedia. Check out what he has to say about FMA.
Tony Lopez: FMA is a term that predates me here at Macromedia. It stands for the Flexible Messaging Area, and it's the section within the Flash portion of the home page where we do important "high impact" messaging. Think of it as an end-cap in a store. It's a display that we hope you'll spend some time looking at, and eventually acting on. We try to tell a simple story here. Sometimes it's about a new product, other times it might be about an event, or a promotion that we are running. We always try to tell this story in a manner that is clear, elegant and engaging. Hopefully we strive to provide some design inspiration, but it's always function over form.
