A long time ago, I'd rolled-my-own temperature monitoring system for my server room (back in my sysadmin days) and it sent me an SMS to my phone. But I didn't need a cellular device to do the sending.

If I recall correctly, I was taking advantage of a feature on my phone's carrier: The ability to receive emails as texts, if the emails were sent to <phonenumber>@att.net or something like that. So, for instance, all I had to do was program my temperature monitoring system to send an email to [email protected] and then my phone would receive an SMS text with the email subject line and a MMS attachment.

I wonder how many wireless carriers, if any, still do the same thing?