Hopefully it's private.

As far as the legal requirements, I believe in the US it's permissible for debt collectors to contact friends/family in order to get in touch with the debtor, but there are certain limitations (like they're not supposed to disclose the amount of the debt, etc).

I think you're right about the practicality issue - I doubt twitter or any other network would want anyone using their platform for that type of activity.

The Chinese courts have been exploring an _interesting_ and public method of debt collection.

http://www.chinadaily.com.cn/china/2017-07/26/content_302507...

Even if private messaging, which social platform has bank level privacy/PII controls in place? How often are they hacked/sold/oopsied?

In Spain and Portugal there's a company that sends people dressed in frock coats and top hats to the debtor's workplace entrance and such, to publicly shame them: https://www.theguardian.com/business/2013/aug/09/spain-debt-...

Both suck.

Perhaps, but on platforms like twitter where the default behavior is to only allow direct messages to mutual followers, I imagine they might use an @mention which is publicly visible - like "@newman8r - please get in contact with us, we need to discuss your car payment" - and they offer to delete the tweet after payment or something.... I guess that would be the worst case scenario. If it's just private messaging then it's not as big of a deal.