Apparently, they have been mulling over the possibility of a Tron 3 for a long time. However, two teaser trailers were released. Tron 3 is going to involve the actions of Alan, RAM's creator, and Sam Flynn as they deal with their titular enemy -- the Master Control Program.
So, far, so good, Disney has a good sequel on their hands. If they don't screw it up, we can get the Rest of the Story. Why Edward Dillinger is working for ENCOM. Why he's communicating with the MCP, and why he was so relaxed as to ENCOM OS 12 being released on the Web.
And why RAM's creator ("Alan, can I have some of your popcorn?") is doing Flynn Lives. The Grid, which Flynn was creating, was to be the evolution of the Net before the Web took over. And it looks like TRON 3 will be set not on the ENCOM mainframe or Flynn's computer lab -- but the Web.