How to Build an SMS Service
ISBN: 789742233
EAN: N/A
EAN: N/A
Year: 2007
Pages: 52
Pages: 52
SMS Interaction Design Considerations > Store and Forward
Like email, SMS is a store and forward system. In other words, the server will receive sent messages and hold on to them until they can be delivered (although, like email, the period during which delivery is attempted will be limited, typically to 24 48 hours).
This makes SMS messaging an ideal way to deliver information or to communicate with someone who has infrequent or unreliable connectivity.
For example, after Hurricane Katrina ravaged the Mississippi and Louisiana coast, I spent a week working with a relief organization, World Shelters, building temporary shelters for the displaced. The work was organized on the fly, with volunteers identifying those in need at relief centers or through word of mouth and then trying to direct the building teams to destinations without the benefit of reliable maps or local guides.
With the infrastructure decimated, cellular coverage was spotty, and thus calling teams to get status was impractical: the odds of both caller and callee having service at the same time was low. Email was out of the question.
Fortunately, we were able to use the Slam prototype developed in collaboration with Shelly Farnham and Scott Counts in Microsoft Research. Slam is a group-centric text messaging service that allows people to send and receive text messages to a group. Messages could be sent with the comfortable knowledge that, even if they weren't delivered immediately, they would be received as soon as the other people in the group moved through an area of cellular coverage.
While disaster situations like that are (thankfully) rare, spotty cellular coverage is not. Thick-walled buildings or theater rules are enough to prevent someone from receiving a phone call. Whether it's a message from a friend letting you know where people are meeting up or a reminder from your calendar, store and forward means the message can still get through as soon as possible.