When the iPhone first came out in June 2007, you could only send one text message to one person at a time. No pictures, no videos, no audio. Only a Short Message (SMS).

Six months later, in January 2008, Apple added the ability for our iPhones to send an SMS message to multiple people. This was a feature of iOS version 1.1.3.

Eighteen months after that, in June 2009, Multimedia Messaging (MMS) was introduced to the iPhone as part of iOS 3.0. However, MMS was only available to people using an iPhone 3G or 3GS, and only to those who were not on AT&T. If you had an original iPhone from 2007, or if you lived in the United States, you could not yet send or receive any MMS messages.

In September 2009, AT&T released a carrier update and iPhone users in the U.S. got MMS messaging.

And the most recent update for group messages came when iOS 4 shipped in June 2010. For those on AT&T sending a group message no longer defaults to many individual SMS or MMS messages. Rather, sending a group message on iOS 4 sends it as a single MMS to many people; even if you are only sending a plain text message.

The easiest way to see the difference between sending a group message that is sent as an MMS instead of an SMS is in the top “Sending” status bar of the message’s window. For a group MMS message the bar steadily progresses until it’s done. For a group SMS message the bar progresses in spurts, as several messages are sent back to back to each individual recipient in the group.

This new functionality by AT&T is called “Group Messaging” and has some benefits for the sender:

• If you’re sending a group message to other iPhone users it means everyone in the group can see everyone else in the group and join the conversation by replying all. In essence, it’s a group chat.

• A group SMS can only go to 10 recipients. A group MMS can be sent to 100.

• Sending a group message as MMS counts as just one message sent. Whereas a group message sent as SMS means you are charged for each recipient in the group.

There really is no disadvantage for sending group messages as MMS from your iPhone.

However, with Group Messaging there can be disadvantages for those receiving your messages:

• Since Group Messaging means messages are sent as MMS no matter what, if you’re sending to people using Blackberries or non-smartphones then they have to open and download your text message as if it contained a media attachment. They think you’re sending a picture, but you simply sent some words. I’ve been told by my friends and family members who use Blackberries and non-smartphones that this is often misleading and always annoying. They were expecting to get an entertaining image from me and instead they got a bland text message. (Perhaps I should be more entertaining with my texting.)

For recipients on Android phones it’s the same issue. They receive your message as an MMS with the subject “No Subject” (unless of course you’ve turned on the “Show Subject Field” option and you’ve written a subject line).

And nobody sees any of the other recipients in the group you’ve sent to except for those on iPhones. It’s only a “group chat” if it’s iPhone users exclusively.

• And lastly, if by chance someone in your group message is using a phone that doesn’t accept multimedia messages at all, then they will simply not get your text. Instead they get an annoying note — sent from you but written by the carrier — that says something along the lines of, “Hi! I sent you a Multimedia Message. You can log onto a website and enter this long password to see it.” (Remember, during those years when your iPhone could not send or receive MMS messages and you would get that annoying message telling you to log in to a website to see the message?) So very annoying.

How to Turn Group Messaging Off

If you’re so inclined, your AT&T iPhone has a setting to adjust the manner these group texts are sent.

Even though these group messages are sent as MMS messages, you can still leave MMS turned on while turning “Group Messaging” off. This means: (a) you can still send media-rich MMS messages; and (b) group text messages are sent as many individual SMS messages instead of a single MMS. Consider it a favor to your non-iPhone-using friends and family who don’t like downloading your text-only MMS messages.

Simply go to Settings → Messages → “Group Messaging”.

According to the good folks on Twitter, the option to turn off “Group Messaging” in the Messages Settings is only available to iPhone users on AT&T. For example, here’s what the Messages Settings pane looks like for an iPhone on Canada’s Rogers network:

(Screenshot courtesy of Pat Dryburgh.)

Though iPhone users on the Rogers network cannot turn Group Messaging off, group messages are still sent as an MMS message just like on AT&T.

For iPhone users on carriers other than AT&T and Rogers I am not sure if group messages are sent as a single MMS message, or as multiple SMS messages. If the former, it seems as if the only way to disable group messaging as MMS is to turn off MMS Messaging altogether. Therefore forcing a group message to be sent as several individual SMS messages.

Turning MMS Messaging off in the Settings only means you cannot send an MMS message (no texting of video, images, or audio). You can still receive an MMS message from someone else.