Speaking as someone who has built this product before, I think you'll run into the same outcome that my product, Well, Bagcheck, Listly, Listgeeks, and others end up at:

It doesn't actually provide any value.

It sounds really harsh, but unfortunately, that's the reality. People show up, make a few lists because it sounds fun, but you don't give anything back to them. You don't end up getting information that isn't already more readily available (and more useful) in other forms. There's this notion that people will carefully curate lists of things they care about, and it's true that they do, but only for a few days. There's no incentive to come back and maintain them because they aren't getting anything back out of it.

You can certainly say that I'm cynical and/or jaded from having built this and seen it first hand, but I think there's a reason why none of these sites ever stick. I don't believe it's due to them being built by bad engineers, or being implemented in a way that doesn't work, it's just that it's a feature and not a product.