The study also found some marked differences emerging among various mobile platforms that suggest mobile video is not as homogenous as some people might think.

"Rather than think of mobile video as one big monolith, people are going to have to think about these as different platforms and [about] how consumers use them," suggests Dave Tice, vice president-managing director of Knowledge Networks/SRI.

For example, while the penetration of video usage is almost the same among iPod users (8%) and video cell phone users (6%), people view video differently on the two devices. On iPods, it's more like video behavior on laptop computers, which is to watch longer-form content, while cell phone users tend to watch shorter videos.

Nearly half (46%) of video cell phone users reported an average video viewing session of five minutes or less, versus 53% of iPod or laptop users who reported an average viewing session of 30 minutes or more.

Tice said the behavioral differences may be due to iPod users generally downloading content by connecting the device to a broadband computer, and thus using the iPod as an extension of the computer. "It might be more of a problem for someone trying to download a 30-minute video on a cell phone," said Tice, adding that the whole orientation of video cell phone users may be different than that of video iPod users--people get iPods to consume entertainment, whereas they get cell phones primarily to make phone calls.

In fact, viewing of feature-length movies has risen dramatically among consumers who utilize the video capabilities of their iPods, jumping from just 1% in last year's study to 54% this year.

Tice said it's too early to determine how new generations of mobile phone technologies--such as Apple's iPhone--might impact those behaviors over time.

One behavior that is becoming clear across all forms of mobile video is how consumers regard advertising. The good news for the ad industry is that four out of five consumers who watch mobile video say they are willing to view mobile advertising in order to get free video content. The bad news is that less than 30% of them feel that mobile ads are relevant to them.

As low as that percentage is, however, Tice doesn't necessarily think it's that bad, saying the percentage is about the same as those who feel TV commercials on regular television are relevant to them. "I think that it's a telling finding, because people don't see ads on mobile video as being any better than television," he said, "but if advertisers are able to use the one-to-one targeting nature of mobile to do a better job of making their marketing messages more relevant to them, then they can probably improve those perceptions over time."