It's a bit easier when you already have a user base of billions. Edit: So I disagree with the article entirely, it's not interesting at all.
Agreed, that having a huge user base of another product helps. But did Google Wave or Buzz take off that fast? I don't think Wave ever probably got to that many users.
Yes, in two days, Buzz had millions of users according to Google: http://tinyurl.com/3gsve3q
I think Google+ is way overhyped. It's currently riding a novelty factor among early adopters of not being Twitter or Facebook. You even get blasted on it if you mention "Follow Friday."