Here are some complete answers from the support page for a new mobile app called Jelly:
How do I create a Jelly account?
Jelly uses your existing social network accounts. You can sign in to Jelly with Twitter and, or your Facebook credentials.
So you can’t sign up to use Jelly without letting it use your Twitter or Facebook accounts.
How do I deactivate my account?
You can delete the Jelly application from your mobile device if you no longer want to use the service. This will not however remove any content you have created on Jelly.
So there’s no way that you can ever delete your Jelly account if you don’t want to use it anymore. The best you can ever hope to do is to remove Jelly app from your telephone.
How do I remove a social network connection?
We currently do not support the ability to remove a social network once authenticating it.
So once you’ve signed up for an account with Jelly, which is only possible via Twitter or Facebook, you can never delete that account and you can never dissociate it from your Twitter or Facebook identities.
There are shitty apps, and then there are apps that are so shitty and so completely and entirely worthless that I’d probably never hear about them to be able to bitch about them on my blog. And then there are stupidly and pathetically lazy apps that don’t support even the most basic elements that don’t even rise to the level of “features” or “functionality.”
Making people sign up for a new app or web service using other services like Twitter or Facebook is totally acceptable and understandable, especially considering how much Twitter and Facebook (and Google) are investing in getting themselves to be the universally recognized services for identity verification, and what a prize that would be, though in time any service that wants to grow needs to allow signup without a Twitter or Facebook account.
But never letting someone disconnect his Twitter or Facebook account and identity from another app? Never letting him delete the content he’s created on that app? Never letting him close his account? That is utter bullshit and Biz Stone, the Twitter guy who’s also responsible for Jelly, knows it. Shame on him.
I strongly discourage anyone from using Jelly for any reason, under any circumstances.