[pyre]

I think that 'subscriber' refers to the account owner as they are 'subscribing' to Twitter's service (in the same way that your ISP considers you a subscriber).

  > The following customer or subscriber account information
  > for each account registered to...

That sounds to me like customer and subscriber are being used as synonyms. Maybe someone else more legal-headed can clarify.

[sage_joch]

Having re-read it a few more times, I think you're right. That's at least a little less concerning than I had originally thought.

[zacstewart]

That sounds more likely. I feel better.