Remind (formerly Remind101) is a communications tool that lets teachers text-message students (and their parents) without exchanging actual telephone numbers. The texting is only one-way: Messages go directly from the teacher to classes of students or parents; teachers cannot message individual students.

Upon signing up, teachers create a "class" with a unique number assigned by Remind. When students and parents send a text to that number, they are subscribed in the class and will begin receiving messages from the teacher via either mobile phones or email. (A smartphone is not required.) Teachers can create up to ten classes.

The system allows teachers to send messages by logging onto the Remind website, or by using the iPhone or Android app. Messages can be sent immediately or scheduled for later delivery. Some teachers have used it to send students a quick query or challenge problem during the day. Others use it to remind students of upcoming assignments and tests. According to the company, teachers who use Remind send an average of 5.8 messages a week.

Remind also maintains a log of all message message history, which can never be edited or deleted.

Remind is also free for teachers and available in the U.S. and Canada. One nice touch: the site's testimonials are from real teachers with their names, school districts and often a picture or twitter handle. It's a refreshing change from generic "Mrs. Jones." 

In July 2014, Remind became available worldwide, and hit the "top five" category for all free apps on the iOS App Store, boasting over one million teachers and 17 million student and parent users. Remind also released a series of updates in August 2014, now supporting structured responses through Stamps and audio attachment through Voice Clips.