The consumer offers do not permit customers to host any type of server, personal or commercial.
And they block port 80 and inbound port 25, the standard ports for HTTP and SMTP.
Too many things could be accurately termed servers for this to be meaningfully enforced without outraging all of their customers. Allow remote desktop connections in Windows XP Pro, and you’re running a server.
Nearly anything useful you could do with any significant percentage of that upload speed could be described as operating a server. Clearly, they have no intent of enforcing the rule to the letter, or they’d be forbidding a lot of things that most of their customers want.
But it gives them a means of cracking down on anyone daring to actually make use of that upload speed.
This is false advertising + plausible deniability.