A few years ago I wrote about , who were in some cases using it as a tool to help students with homework. There were instances even then when teachers got themselves into sticky situations.

Facebook is quickly becoming the social network of choice and is also increasingly serving multiple purposes.

People post their vacation pictures on Facebook and exchange banter with friends, but it's also often a place to post jobs and share links with peers and colleagues.

Sree Sreenivasan, a Columbia University journalism professor and the Dean of Student Affairs, has a whopping 3,584 friends, and they include many students and former students.

Sreenivasan, who is also a tech reporter covering Internet trends for WNBC-TV and WNBC.com, told The Industry Standard that professors should be thoughtful and careful about what they post to Facebook. If necessary, he advised putting students (and others) on Facebook's limited profile.