In a blended learning environment, you can encourage communication in many ways:
1.Padlet
Padlet is a virtual wall that allows people to express their thoughts on a common topic easily. It works like an online sheet of paper where people can put any content (e.g. images, videos, documents, text) anywhere on the page, together with anyone, from any device. Site: http://padlet.com
2. Remind
Easily communicate with your students via texting without needing to know their phone numbers OR without their needing to know your phone number.
Site: http://remind.com/