I don't really like my cell phone very much. I have a few friends, however, who see a cell as an extension of their body. They can thumb a text message at amazing speeds. Most younger people can use a cell like I use a fork too. That's important because they are the people most likely to surf mobi. Most of us, at this site, use computers and prefer computers (there might even be some mobi site owners that have never seen their site on a real mobile device, just that emulator). The cell crowd is a totally different type of user and that's best to notice. They are totally comfortable tapping in text Smessages at high speed with their thumb (I'm a novice, I use my index finger). Thumbing messages is a skill and not a trying task. So, when you think of names for MOBI, keep in mind who is using the medium. Don't base decisions on how computer users relate to cell phones and the Internet. Focus on how cell phone users interact with the cell phones and the upcoming mobile web. Short names are still great (popsongs.mobi), but NewPopSongVideoHits.mobi is a lot better than npsvh.mobi which won't mean a thing to a keyword driven search engine.
Speaking of Search engines: On my phone, it is easier to type in search phrases than a URL. A search box is the first thing with which I am presented. That's something to really consider. Also, if mobile companies start screening for sites that have mobile compatible content (and blocking out the rest), the length of the domain name might become totally irrelevant. People might use a search box instead of typing a url in a browser. Which means: keyword keyword, keyword.
I might be wrong, but that's what I think. Any keyword mobi is exactly the right length: short or long.
