Should teachers be banned from interacting with students on social media websites?

What is a social media website?
Social media are computer-mediated tools that allow people to create, share or exchange information, ideas, and pictures/videos in virtual communities and networks. E.g. Facebook ( http://en.wikipedia.org/wiki/Social_media )

Points for:
1. It can enable sexual misconduct
2. The teacher's personal life could undermine the educational message

points against:
1. Teachers can monitor what students do
2. Banning students from talking to students can be said to be a violation of their freedom to speech right

I think its perfectly fine tbh. But to a certain extent, only because of the nudity and possible pedophilia.

When i was in college and secondary school teacher were allowed to communicate with their pupils on Facebook and such but the teacher needed to make a second account which did not contain any of their 'Night outs' and so on, this meant that teacher had to make their main account totally private.