A few months ago, Omar Shahine wrote about how various folks in our org came together to get the MSN Mobile Messaging feature to work. This feature allows people to have IM conversations with people using a cell phone via SMS using MSN Messenger. In his post When the work you do is architectural (MSN Mobile Messaging) he talks about the feature and how it was implemented on our various back ends. Some of his post is excerpted below  

So what to do? Enter MSN Messenger to SMS communications (we call this Enhanced mobile messaging). The feature we've been working on for the past year (or longer) was to allow a user of MSN Messenger on a PC to send a message to some one that is not signed into MSN Messenger but has an SMS enabled Mobile device AND to reply to that SMS message and have a real time chat (in otherwords, a two way conversation between MSN Messenger and Mobile phone using SMS as the wire protocol). This last part is important, but to understand it I need to explain one more thing.

For the past few years part of the scenario above has been available through what I will call a hack. Most phones that have SMS also have an email gateway that can take a message sent to a special email address and forward that message to the phone. For example, an email sent to <phone number>@mmode.com will forward that message via SMS to the <phone number> of an ATT Wireless subscriber. However, the user cannot reply to that email enabling a 2 way chat. Furthermore, it breaks the SMS user experience that mobile phone users are used to.

So, to fix this we set out to build all the necessary carrier infrastructure, SMS infrastructure, and build the technology and carrier relationships to ship the ability for users to have a two way conversation from MSN Messenger to a Mobile device that has nothing more than SMS capabilities (practically every singe phone on the planet). Not only that, but we support "Offline messages" so that if a Mobile phone device replies to an SMS from Messenger, and you have signed out of MSN Messenger, the next time you sign in the message will be delivered to you allowing you to continue the conversation.

I was reminded of this today because of his follow up post MSN Mobile Messaging for Cingular, which let me know that my girlfriend's cell phone carrier is now supported. Sweet.

Omar's original post has some interesting details on some of the issues they faced in bringing this feature to the market. This is an awesome feature and I'm definitely going to get a lot of use out of it.