[dshingarev]

Thanks for your comment!

The reason we decided to use FB only auth is that we felt that in order to provide the same feature set with FB and without it would require quite a lot of duplication on our site. And the more social features we add - the more duplication it requires.

For example, for a plan you can specify "friends only" visibility - and for this to work we need to support friends lists in our app. We also use FB to send SMS reminders (if allowed by a user) - and that's not the easiest and cheapest thing to implement from scratch.

[stevenwei]

I'm not suggesting you duplicate the feature set that Facebook provides. If a user wants to have those features, it makes sense to have them link their Facebook account.

But I would probably offer a more basic version that doesn't have friend lists, SMS reminders, etc, and let the user opt in to the additional features only if they wanted to. Otherwise I think you might end up artificially restricting the amount/type of users that use your site (e.g. people without Facebook accounts or people that want to keep their Facebook data private).

[dshingarev]

Maybe you're right... We have to think about it more carefully. Thanks for your feedback!