Another service which tries to bridge IM and SMS. I’m pretty sure it’s going to be incredibly hard to provide a good user experience at scale. SMS is mostly asynchronous while IM is not. It becomes hard to use IM if you don’t have some sort of control over the latency of the messages, and only a very brave person would claim that they can guarantee message latencies in mobile networks. Even if you imagine for a moment that a service has the capacity required to push messages into an operator’s network at the rate in which they are generated (which is highly unlikely considering the cost), there is no guarantee that they’ll make it to the handset on the other end in time. SMS uses a store and forward process like e-mail, and shares some of the same characteristics. It is simply not a reliable medium for time sensitive communication.