It's obvious what I meant. I don't know why you people are trying to hard to play the semantics game.
I'll put it in a more succint fashion: You don't need a data plan to send and recieve MMS. The protocols phones use the send and recieve that stuff as well as the format of the media and compression methods are all standardized. You don't need a data plan for that. MMS has existed since LONG before smartphones became commodity devices. Dumbphones can send and recieve them, and they don't require a data plan.
What a smartphone requires [here] to send MMS is not even a factor since either:
1. The carrier will not allow you to use a smartphone on their network without a data plan. AT&T being the obvious example, they will automatically give you a $25 2GB data plan if you take a SIM out of a feature phone and put it into a smartphone. This happened to my mother, actually. You can get them to take it off, but they will tell you to put the SIM back in a dumb or feature phone. If the smartphone registers on the network again, the system will automatically add the $25 data plan.
2. Smartphones without a data plan are almost useless, even if you have WiFi coverage in 50% of the places you congregate, assuming your phone isn't off the other 50% of the time, of course. WP7 is worse off than iOS or Android without a data plan because of the way the cloud services are integrated into it, encouraging people to put their data on SkyDrive, Zune Pass streaming, Low-Capacity Devices, etc.
AT&T will probably be the only major carrier here to get high end Nokia WP7 device earlier. It will be impossible to use tho phone on their network without a data plan. Whether or not MMS uses that is a non-factor.
I've yet to see a carrier that charges its users data charges for sending and recieving MMS. MMS are charged on a per-message rate, like SMS.
I don't know what other carrier in other countries do. But charging data for MMS is not normal or expected here.
I personally don't know anyone - at all - who has a smartphone (here) without at least a 2GB data plan. It's really a bit of a moot point.
The main issue isn't what the MMS requires, but the outrageous prices that carriers charge for SMS/MMS packages. Unless you have a family plan with a family unlimited SMS/MMS package for 3+ phones it's a total rip-off.