First, implementing technology requires a lot of setup and learning time before the teacher can use it effectively in the classroom. Another point to consider is: who will provide the devices that students will use to access social media? If you are relying on students to bring their cell phones from home, then there are several questions to consider. Does everyone have access to a phone or tablet? Are their devices charged? Do everyone's devices have the same functionality across the board? If the school has the resources to provide the technology, will it be available and working when you need it? While these are just some of the certainly valid reasons to hesitate, I think the positives outweigh the negatives.