This is a subject of much discussion, particularly on the uk-freeforms e-group, where every so often people try to define exactly what the term means, and normally end up deciding that it means different things to different people.

What I mean by a freeform is probably best summed up by a quote from Steve Hatherley's web-site:

What's a Freeform?

Freeforms are similar to Murder Mystery parties - but you commit the murder yourself. Freeforms are a little like plays - but without a script or audience. Freeforms are rather like roleplaying games - but lack the tables, dice and have many, many more players.

On the other hand, SFC Press describe freeforms as "an interactive social game in which you assume the identity of a character and try to accomplish goals by talking with other players and using simple game systems to handle such things as combat, romance, etc."

You know, it's a lot easier to play in a freeform than it is to explain one.

The sort of freeforms that I enjoy playing and developing are the sort of plot-heavy, single-session, pre-generated character games like Café Casablanca, 1897 - Queen Victoria's Jubilee, Kings Musketeers, Torch of Freedom, our own Siege of Troy, Tombstone and  Here be Pyrates!