I'm sure there are many other reasons, but also, at the time it rolled out (and/or when they integrated Postini), Gmail was sort of a miracle cure for spam. Ju

I'm sure there are many other reasons, but also, at the time it rolled out (and/or when they integrated Postini), Gmail was sort of a miracle cure for spam. Just sign up, and spam-be-gone. A lot of people wanted such a "fire and forget" solution.