Is a comment section user-to-user, though? On its face, it seems more user-to-public, since it's not a private user-to-user transmission. If blog comment sections are exempt, it would seem Reddit is exempt too.
“provider content” means content published on a service by the provider of the service or by a person acting on behalf of the provider.
It's unclear if there's a difference between hosting your own blog, or using a blogging service, because the bill is terrible.