If we define it as technology-assisted one-to-many bi-directional communication (therefore ruling out the telephone, letters, and so on), I think there's an argument to be made that it was the newspaper. In the old days, particularly pre-television, local papers in particular would have a lot of mini-stories just about what people were doing with their lives. If we define "technology" as "the internet", I think it probably really is finger - 1971 is pretty early on, pre-dating usenet by almost a decade and mailing lists by more than that.