Your twitter account is worth up to $20 to someone who needs to buy twitter...
Your twitter account is worth up to $20 to someone who needs to buy twitter accounts. (Annual fee for new accounts divided by interest rate). But if old users don't value their old account much, they might be willing to part with it for a significant discount, far less than $20.
What are you going to sell your legacy account for?
Self-replies
$1 per year. Seems like this friction would mostly stop users from signing up at all. Did they check with real consumers to see what their willingness to pay was?
They could have just asked to have a credit card on file & charge $0, as a way to prove you're a person. Seems redundant with the phone thing too.