Geishas still exist. They're not assasins. But there is this movie called "Memoirs of a Geisha" And that's where I learned things about geishas. They're entertainers and they are masters of converssation, like what Nympho said. I have to agree. ^^
And yes, it's for the men, those sexual acts...
You can learn more about geishas in Wikipedia.Org... You can learn about the old-time geishas before either World War I or II, I'm not quite sure, and the modern geishas who still follow the traditional ways of the old-time ones but I think they are somehow different... ^^
That's all I know. If I have a mistake, anyone, please correct me. ^^