google+ had a few advantages when it started, comparing to both twitter and facebook. first of all, google+ is a success because twitter and facebook already existed. people want to see what the new social network looks like, as they want an alternative to facebook. facebook had to reach that number without hype and ads. second advantage is that google is a giant and everybody has heard of it. no wonder than that people want to see what their new product looks like. having said that, google+ is a success mostly because it works. even with those few kinks and a beta-feel to it, it works! i think the great question is: will it continue to impress? at some point, they will have to add ads. how will the ui look like then? facebook is all cluttered and ugly, but it wasn't like that in the beginning.