Some players really enjoy and are motivated by leaderboard type features, and other players can get quite fed up with the competitive nature of leaderboards. For me personally, I don't play social games to compete with other people - I just like to casually enjoy working on my own tasks at hand. I can definitely understand how competing with friends can be a major driver for in-game interaction and engagement though, so it makes sense from Zynga's perspective to add this type of feature.
What do you think? Yay or nay to competitive leaderboards within your social games?