Not really. Some products like YouTube used a separate account. Most products had incompatible ToS so any integration was difficult or impossible. Each product that had comments, like YouTube or Blogger, or a concept of marking something as good/bad/favorite/starred/etc., or sharing, did that in a different and incompatible way, etc. The gmail account was only good enough as a basic authentication token for several products, nothing more. Yes, we could have fixed all these problems by unifying all these features around the gmail account without introducing a traditional social network as a 'bonus' (one that not all users want), but guess what? If you upgrade your account to G+ but you never post in the stream, or circle anything, there's absolutely no difference to that hypothetical scenario of "full integration without introducing plus-the-social-network". Just go to plus.google.com/settings and disable everything and be happy.

> Just go to plus.google.com/settings and disable everything and be happy

Until they add more things that are checked by default like that "let any random yahoo email me" feature.