Edublogs is a great service to use for student and parent communication. Clyde Elementary and Intermediate teachers have grade level blogs for communication with parents. They subscribe via email for updates on information and assignments. Junior High and HS teachers have parents as well as students subscribe to their blogs for information updates. Organizations and extra curricular activity blogs (Theater and Athletics) at Clyde CISD have blogs where everyone from the newspaper, community and extended community have subscribed to receive updates and information on game changes, rehearsal times, meetings etc..
Remind 101 is a free service for teachers to communicate with parents and/or students via text messaging. Teachers create groups/classes to quickly deliver information in a text. Students and parents are given a code to subscribe and no one has to ever exchange phone numbers.
QR codes are an efficient way for people to get information via a mobile device. QR codes eliminate the need to type in the long url to visit a website, and allows to scan the QR code (with a QR code reading app) and go directly to the website from any device.
Twitter remains my favorite place to grow my professional learning community. (That opinion might change tomorrow.) By creating a community of people that share information relevant and necessary to my needs, I save time and always have the latest and best information delivered straight to me instead of searching for hours to find one decent resource.