A little while ago I was checking out a new mobile site and I was suprised when I read in the help pages something like, "to post, send a text message to email@example.com." I was quite taken aback. Text message to an email? No, that's not right. Though it may be available for some operators, SMS needs a phone number, not an email address. What they were talking about as MMS messages. That's when the patently obvious dawned on me:
Camera phones are all MMS enabled and MMS uses SMTP and thus is basically email.
Of course there's some caveats to that sentence - MMS assumes GSM, and MMS to email assumes the carrier allows this sort of thing. But in general, it's a good assumption that if you have a camera phone, you can send an email automagically from your mobile. Even Yahoo Mobile's Photo Upload instructions assume this: "Email or MMS your pictures to firstname.lastname@example.org," it says. Huh.
So we all know my opinions about *receiving* MMSes (it just doesn't ever seem to work) but sending these messages? That's a whole other ballgame. So this morning I wandered around the office and had my coworkers send me an email from their mobiles using the most basic functionality possible. The same way a newbie would send an email from a mobile.
AT&T Wireless: I sent a message from my Nokia S60 phone. SMS won't let me enter in an email, so I chose a "Multimedia Message" instead and the message came through pretty instantly as a basic Email. The return address is in the format: email@example.com. I've done this before, so I knew that bit. I copied and pasted a long message and replied, but only got an SMS in return, with the first 160 characters.
Cingular: I had my coworker Todd do the same thing from his S60 phone using Cingular and got the message with the return address of firstname.lastname@example.org (notice no country code). It too came through as a plain email, but with a bunch of text at the bottom: "You have received the above Multimedia Message (MMS) from a Cingular Wireless customer," etc. I responded with a bunch of text and surprisingly (or maybe not considering the domain name) Todd got a full-on MMS message in return with all of the text. Subsequent tests with Images didn't work, but still... that was very interesting.
Verizon: I had Vineet try with his shiny new Motorola V710, and got an email from email@example.com, which had no extra text or formatting. I sent a bunch of text back, but he only got a TXT message with the first 160 characters or so.
Sprint: I had Joel send me a Picture Mail from Sprint, and got the standard HTML message with the image attached from firstname.lastname@example.org. In case you don't know, embedded in the HTML is a hidden XML fragment which point to LightSurf's servers so you can grab the attached image if you want to. Responding with a lot of text, Sprint too only sent the first 160 characters or so in a basic text message.
Nextel: I had ScottC send me a text message from his shiny new i830, and he was surprised (as most people are) to see the field say "Enter Phone/Email". I received an very basic text email from +email@example.com. Replying with a bunch of text only sent the first 160 characters or so.
T-Mobile: Finally, I had Matt send me an email from T-Mobile and got a message from firstname.lastname@example.org - the message was in HTML, but so broken Thunderbird couldn't read/format it so it appeared blank - it also didn't have a subject. Responding with a bunch of text sent an MMS (like Cingular) so that was pretty cool.
So the conclusion is: Wow. They all work. I'm not sure how reliable or stable these systems are, but if you wanted to launch a mobile service which relies on messaging like Yahoo Photos did, you don't have to worry about a special SMS or MMS phone number, you can simply have the users (at least here in the U.S.) enter in an email address. The challenge of course, is to work through the permutations of email formats to best extract the text and media content, and exclude the attached images from HTML message like from T-Mob and Sprint.
And what about sending? Well, this is a bit more interesting. Plain text SMSes will still work most reliably. But it seems to me that a startup could skip this step as well, by simply knowing the format of the carrier's email-to-mobile address. But you can't rely on this at all - I know from experience.
Back a few years ago, I was toying with the idea of these types of alerts and played this game with Telefonica Movistar. At first, SMS messages sent to their email gateway would arrive as sent to the user. But eventually they changed to an online web-mail system where all you got on your phone was an alert that said "you have a message waiting for you in your online mail account". Obviously they did this to make sure that companies did not use the email gateway for exactly what I was thinking fo doing with it - to skip around the SMS charges.
But the U.S. is a bit different - email is much more ingrained and if a user wasn't able to send or receive email like this, there could be an outcry. Also, I'm sure that T-Mob and Cingular charged for that MMS message that was *received* and were quite happy to allow that functionality. I wonder if they have plans for SPAM? I once stupidly posted an email to one of my prepay phones on this site and paid the price with *loads* of mobilized spam messages.
It'll be interesting to see how this evolves and how both developers and carriers use and adapt these services.