I had read about this awhile ago. It was posted on a sign along the B&A. I have a slight fascination with incredibly long distance trails. Having hiked a good portion of the central Appalachian Trail, I find the idea of a parallel bike route to be absolutely awesome. The East Coast Greenway is an attempt to create a complete trail from the northern tip of Maine to the tip of Key West, Florida. (The AT goes from Georgia to Maine). So basically, an East Coast bike path that I could get on and go visit my cousins in Florida or hang out with some friends up in Maine.
Their Maryland Section is coming along nicely, although I really question their want to go through inner city baltimore. I mean... gross. Either way they are using the B&A path and BWI Loop as segments along it. I really want to go out and ride the rest of this area, I've never heard of most of those routes!
And speaking of long distance cycling, check out some of the Bicycle World Records!