Hi! If you're asking about jams in general, it varies a lot from event to event. Some have prizes, some don't. Some have a couple of participants, others have thousands. Some get media coverage, others don't. Some are one-off events, others like Adventure Jam are recurring.
For Adventure Jam specifically, you can read more about the people behind it here: http://advjam.com/about/
Historically there's not been a lot of media coverage of Adventure Jam that I can recall. That's not something organisers have put specific effort into pursuing, but it can happen organically. These days, jams happen so regularly that most game focused media don't consider them noteworthy.
Adventure Jam doesn't have prizes beyond whatever you make and the experience you gain making it ^_^