Do I use it in my classroom? In a nutshell, no. Why?, That's simple. My students are 7th graders, so 11-13 years old and it is against the law for them to have social media accounts. Now, do some of this age group have social media accounts? Sure. Some of them. But, definitely not all of them and I don't believe in encouraging them to break the law, or going against their parents wishes by encouraging them to get into social media.
In my opinion, social media is something that students can wait until high school to use in the classroom. I believe there are plenty of other media sites elementary and high schoolers can use such as kidblog.org which are safe, easily monitored and set up for schools and teachers to use. That said, do I think it is useful for high schoolers? Definitely. I think it is a great tool to use to engage kids and meet them where they're at. For example. teaching metaphors through Instagram photos is brilliant. I do think it would be hard to monitor who is posting what though and there is a level of trust between student and teacher that would need to be set before the process in case of any online bullying or inappropriate language etc. that the teacher may find herself dealing with.
All in all, I think that with careful execution and a lot of consideration, using social media with high schoolers could be a great tool.