"Delayed Messages" are an onoff exclusive feature...and they're super-cool!
Basically, a delayed message is a normal SMS, but you can specify the specific date and time that you would like your recipient to receive the message.
You type it as you'd like it to be seen, then simply schedule when you want it delivered. Then we'll send it for you when you want us to.
No more missed birthdays and anniversaries ;)
Check out this post for more info: How Do I Send a Delayed Message?