Facebook can be used in a multitude of ways. Being one of the most prominent social media sites, I think it is the easiest to use. You could start a page of just your classroom so parents can keep up to date on what they students have been doing in your class. Our school has one for our district. It is loaded with any information or links that a parent or student may need. Here is the districts link so you can see it.
https://www.facebook.com/SWVDistrict