Yes, this is something that the user would have to check out. My ISP is Comcast (a regular consumer account, not business). My contract specifically says that I am allowed to run servers from my home, as long as they aren't intended to be used by the general public.

I've been running my own servers from home for a very, very long time and it has never been an issue.

Running a social media node would probably count as "intended for the general public", but I'd bet that Comcast wouldn't really notice or care unless the amount of traffic exceeds a certain level or they start getting abuse complaints.