It seems like it would be the first time someone has done it properly. What is so beautiful about Twilio is their attention to detail for developers - amazing documentation, samples, etc so I am assuming their MMS implementation will be as clean. Here's hoping.
mBlox, OpenMarket, Mobile365 all tried to implement the half assed MMS implementation forced on them by the carrier market and it was an absolutely nightmare. I'm surprised noone in the tech press ever did a deep dive expose on just how archaic the whole certification process was, and the user experience was terrible.
Summary: this is not the first time the carriers have opened up MMS. Hopefully it will be the first time developers can leverage MMS the way it was intended.
Lots actually. MMS is hard - multiple devices with no consistency, different interconnect gateways that can mangle messages along the way. An easy to use, reliable and pervasive MMS gateway isn't as easy to implement as some might think and the carriers haven't made it a priority. In fact the US carriers completely messed up their early MMS implementations with Washington-style regulation that made the user experience beyond horrible. Here's hoping Twilio makes some progress with this and I wish them much success.
EDIT: I realized that I didn't actually answer your question. MMS can be supported by carriers in different ways but the most typical interface is MM7 which is SOAP over HTTP. There are many MM7 gateway vendors and they all handle MIME boundaries, payloads, transcoding, etc different - subtle differences, but enough to make testing against a large matrix of devices very, very hard.
mBlox, OpenMarket, Mobile365 all tried to implement the half assed MMS implementation forced on them by the carrier market and it was an absolutely nightmare. I'm surprised noone in the tech press ever did a deep dive expose on just how archaic the whole certification process was, and the user experience was terrible.
Summary: this is not the first time the carriers have opened up MMS. Hopefully it will be the first time developers can leverage MMS the way it was intended.