To clarify some of the other responses:
SFML is a framework that lets you draw sprites and graphics in any manner that you choose. You can also play any kind of music and sound effects that you choose. It also has a networking module, which allows you to send and receive pretty much any kind of data that you want to/from a remote machine or server.
Basically, SFML only gives you access to graphics/sound/networking resources in a cross-platform way. It doesn't assume anything about what you actually do with those resources. It doesn't even have to be a game, technically. Could be a simulation. Could be embedded into a GUI application and used for rendering graphics for an editor. It's all completely up to you.
