Personally, I've hated "addictiveness" right from the very beginning. There used to be a time, about 5 years ago when people would brag about how addictive their games were. Sid Meier does it all the time. These 'social games' and modern MMOs show that addictiveness is a bad thing. I got hooked on those games for a while. After a few months.. I realized that I just wasn't having any fun. I found myself wondering why I was playing Tycoons on Facebook instead of Capitalism 2, when Capitalism gave me a compressed experienced, instead of this crap that only let me take one small step a day.
However, I'm not all against "Social Gaming". It's just been very poorly implemented, because punishing your customers brings in money. Zynga was an evil, evil company right from their first games, succeeded only because they forced their customers to spam.
The problem with social games is that they use the social aspect as a form of advertising, not as a serious gameplay mechanic. If you can actually have fun with your friends... as in real fun, not just "help fertilize my crops or i lose", then it'd be good. I was thinking of building sort of like a football game in Facebook, where you take control of a football player, log in and train him daily. Then you gather up some friends, build a team together, and play in a league style. If someone doesn't want to play the game any more, you can just put them in reserves. That way, communication with your "friends" is still needed to form a good team.. it's not just a "invite 5 friends to unlock a bigger farm" mechanic.
The only "social game" I still enjoy is Cyber Nations. As with the others, game mechanics are rubbish. But the fun is purely in communicating with others - what social games should really be about. It forges real friendships, and accomplishes a lot of the goals that they set out to achieve.