Today's useless fact - What is the origin of the term "soap opera"?

The shows for the most part in the early days were, of course, geared toward housewives, given the fact that they were home during the day. What did housewives do in those days? Laundry. Thus, the soap companies attached themselves to these programs and were usually the primary sponsors, sometimes even getting recognition in the show titles...which would have been something along the lines of "Palmolive presents All My Children" or some such.