A classical liberal is today's American style conservative/libertarian.
The modern Left traces its roots to communism, obviously, and accomodationist monarchism (a la Bismarck), not so obviously.
And an excess of Rousseau, Marat, and de Sade?
You are correct. When I joined FR yesterday, I wanted the screen name "classical liberal", but it was taken. So I settled for market liberal. Surely no one on here will think that any of my views fall in line with modern liberalism.