Welcome back, “Kotter.”

Time Warner Inc. announced Monday that it would make more than 100 old television series – including “Falcon Crest,” “Kung Fu” and the ’70s sitcom that made John Travolta a star, “Welcome Back, Kotter” – available for free in the first major archive of TV shows on the Web.

When it launches in January, the joint venture between Warner Bros. Domestic Cable Distribution and America Online could help TV, Internet and advertising executives gauge the appetite for longer entertainment programs on the Web.