For the month of May, we're going to try out the Glow Chat System by adding a global channel. It is possible that you'll think of it as the 'public channel' but it is called "Dreamchat". The usual sorts of commands will allow you to access it, such as 'dreamchat', 'dc'. As I am lazy, I leave the other aliases as an exercise for experimentation.
We'll be trying out a variety of settings throughout the month. This week, the channel is configured so that it has to be turned on each time your character connects (unless it is already connected). The channel WILL NOT announce when someone has started listening to the channel.
It is a public channel, anyone might hear what you say on it, so be conscious of that when you use it. Don't have conversations on it that you intend to be private. As always, be careful not to reveal privileged in-character information, do not use the channel as a way of speculating about player alternate characters, and try not to 'reveal your secret identity'. Play your cards close to your chest, just like a superhero. 
We're trying it out from 2012 May 1st (Midnight-GMT) through 11:50 PM GMT on May 31st.