Flash Media Server means Adobe software running on the server, so users would either need to arrange the license themselves and pay for a server (e.g. using EC2

Flash Media Server means Adobe software running on the server, so users would either need to arrange the license themselves and pay for a server (e.g. using EC2) or have a specific service offered by Amazon (what they've just announced). Anyone who wants to serve content without flash doesn't need Flash Media Server, so they can do it without needing this service.