The announcements about mobile in-game advertising came out of last week's Electronic Entertainment Expo (E3) pretty much as expected. Hot on the heels of Microsoft's recent acquisition of in-game network Massive, Bill Gates was touting the potential of cross-platform gaming, from PC to Web to Xbox Live 360 to mobile.

Ironically, the most under-utilized part of the mobile phone for marketing is voice. Texting, WAP, and mobile TV gets so much attention these days that it is easy to forget that the spoken word is still the most powerful, certainly the most popular, mode of communication at work on the handset.

Now that every marketer worth his or her salt has a short code, a wallpaper, and ringtone, we are entering into that challenging but exciting time in any medium when the players actually have to be creative.

By giving college student users some free wireless airtime in exchange for viewing up to four video ads a day on their handsets, Xero Mobile's scheme enjoys the distinct advantage of being both novel and a bit audacious. But do the Xeros add up to a viable plan?

Months ago, we started this column predicting that a fully ad-subsidized wireless service would emerge in the next year. Right on cue, the dubiously named Xero Mobile popped onto the radar this month with plans to exchange free airtime to college student subscribers for watching a set number of video ads each day.

Vegas doesn't have much for me. I don't drink, don't smoke, don't gamble. So my only option at the CTIA Wireless Show in Las Vegas last week was to scratch beneath the surface of the panel sessions on mobile marketing and catch a few rumors and innuendo....

One of the original aims of this column was to highlight good work, to shout out and dissect the more creative uses of the mobile medium for extending brands into pockets and starting conversations with consumers on the most personal medium.

Using mobile phones as couponing devices was one of the first good ideas for this platform, and an early success for a now-famous Dunkin Donuts latte promotion. SMS makes this a fairly easy thing to do, and I am a bit surprised that more of it isn't going on....

As video podcasting and cell phone media evolve on parallel tracks, we are bound to see a lot of cross-pollination and kinships evolve between these platforms.

OK, OK, we get it. Major brands are speed-dialing into mobile marketing plans at a pace that makes their previous move to the Web seem glacial by comparison. There are no hard numbers yet to show how much actual revenue is starting to flow into mobile, but we do know that intentions are running very high, perhaps too high.