Mail a Letter Online you send them an email, they print it, stuff it in an addressed envelope, affix postage and mail starting at $1.52. I can see this for sending to: parents and grandparents, and kids who don’t have email, to people who rarely check their email (you know who I’m talking about) and for instances where you need the impact of a real snail mail letter. I can see this being used by people who travel a lot and are never in an office.
Source: BoingBoing