JotYou is a unique SMS service which takes into consideration your location. It means your text message will only be received once the recipient reaches a certain location such as school or restaurant.

It's simple yet amazing service which you can use to remind of yourself or others once they are in certain locations. First you need to sign up at JotYou (It's free). The follow these simple steps:

Send messages from your computer or mobile phone. Send to one friend, many friends, or just yourself. Specify a location so your friends get a message when they arrive at school or the mall. When your friends arrive at the location you specify, JotYou alerts them by sending your text message to their cell phone, and delivering the message.

Aside from that, it can also be used for social activities like fun games, events, and contests.

via KillerStartups