MMS is short for Multimedia Messaging Service. AT&T is making MMS, which lets users send text, photos, audios and videos across the network, available on the iPhone, iPhone 3G , and iPhone 3GS.

To activate the new service, users need to connect the iPhone to a computer and click "Check for Update" in iTunes. Once the update is completed, AT&T said, users need to restart the iPhone by turning it off and then on again. The iPhone OS 3.1 software is required, so consumers who haven't upgraded the operating system need to do this first.

The Social-Media Connection

"From the standpoint of the AT&T portfolio, every other phone could do MMS, but the iPhone could not," said William Ho, a senior analyst in the wireless services division of Current Analysis. "I think the original thought was that people who used the iPhone could just take a photo and e-mail it, and that would serve the same function. But the problem is you can't always e-mail it to another handset."

Ho said MMS lets users bypass the e-mail functions and send multimedia files directly to another handset. With the rise in social networking, this has become an important capability because many smartphone users rely on MMS to update Facebook accounts with new photos and videos generated on the device instead of uploading through a smartphone app.

Time spent on social networks and blogs has nearly tripled in the past year, accounting for 17 percent of the overall time spent online in August, according to the latest numbers from Nielsen. And more than 18.3 million unique U.S. smartphone users turned to their devices for social-networking access in July, up from 6.4 million users a year earlier.

"Smartphone users want to be spontaneous. They don't want to have to type out the e-mail address every time they want to send a photo or update their Facebook," Ho said. "In addition, some people may not have smartphones, which means they can't receive the photos via e-mail, but they can use MMS. So regular feature phones can get photos sent from the iPhone now."

The iPhone Impact

Ho said MMS opens up more uses for the iPhone. Of course, it comes at a price. Messaging plans begin at $20 for unlimited messaging. Consumers can also purchase 1,500 messages for $15, or 200 messages for $5. Consumers who opt not to subscribe to a messaging plan will pay 20 cents per text message and 30 cents per picture or video message.

Analysts don't expect this to cause a new wave of Apple iPhone users, just as it didn't prevent hordes of consumers from purchasing the iPhone to begin with.

"Apple lovers will rejoice over MMS, but I don't think it was a feature that stopped people from buying. People who wanted the iPhone have been looking past that feature. This is kind of a bonus," Ho said. "The iPhone follows the industry norm now. There are a certain group of people who wanted it and felt like they were cheated by not having it. They felt like they were robbed."