Mosio, if you aren't familiar with the service, can easily be described as a mobile version of Yahoo! Answers (our coverage here). You ask a question by texting from your mobile phone, and you get a response from the community.
Now, they've launched a mashup called Twitter Answers. To use it, you need Twitter and Mosio accounts (both free), and then you need to start following this Twitter "user:" twitter.com/qna and set notifications to "on."
The next step is to ask the question; you do this by sending "d qna your question" through Twitter where "d" starts the direct message, and "qna" is the username. You will get up to four answers for each question you ask. It all works through your mobile, too.
The problem with this service is that most Twitter users, especially those with lots of followers, will probably simply resort to using Twitter itself for their inquiry. However, the idea that Twitter can be used for mobile Q&A is an interesting one; Twitter seems more and more to me like a tool that's pretty much useless by itself but it can be used in many interesting ways.