A fellow student at my university is too nosey with social media. What to do?

[MM]

In addition to JJ's advice, ask your professor if s/he can send around a reminder that all announcements go to everyone in the class and that there's no need to forward. Or just take the woman aside and say, "Look, I know you're trying to be helpful, but it's really coming across as patronizing." One of the problems women often encounter in the workplace (and in general) is not being assertive enough, so don't be afraid to politely but firmly set boundaries before the annoyance gets out of hand.