Birds (sic!) do it, bees do it, even educated fleas do it, and now even Oprah (have you been there before her? Check here)... so: what about mobile games companies tweeting? Now, there's many of them already out there (see list below) but how much sense does it make (that it makes sense for your business I demonstrated recently)?
Looking at a few of them, you'll find anything from very 20th-century in-your-face selling (probably not so efficient) to enlisting (or trying to) followers to help in everything from game design, logo colours to community components that should go into the next iteration of the website. And it is in the crowdsourcing where I see a bit of potential: most mobile games companies are fairly small, and money to spend on sophisticated research, focus groups and what not is scarce or AWOL. If one can draw on the opinions and insights of friendly followers to learn about their (the consumers') preferences, this is surely all good. Since Oprah is on there now, too, there is even a chance that your followers will not only be fellow industry professionals...
Although, even to the industry, Twitter is as powerful a tool to the mobile games people as to anything else (maybe with the exception of the global car-wash industry - everyone who's been to CTIA Wireless will understand the reference): it is a great channel to get the message out to people who matter to you (and who actually show that they care by following you), which puts trade marketing (even if not in the strict sense of the word) onto the list on why you should do it.
So here's a (surely incomplete - please excuse and feel free to add!) list of mobile games companies who tweet:
Connect 2 Media (yes, that's us): @connect2media
Oasys Mobile: @oasysmobile
Hands-On Mobile: @handsonmobile
Digital Chocolate: @dchocgames