Charles Pax has developed a working MakerBot motorized conveyor belt print bed.  (Is it heated?)  There’s a lot of reasons why this is a big deal:

1. This is the fourth MakerBot “milestone.” We’ve reached milestone #1.  Milestone #2 (different threaded rods and internal electronics) and #3 (Gen 4 electronics) are noble, but not really transformative goals.
2. Continuously cranking out parts is a way to turn a simple MakerBot into a portable factory – rather than a modest means of prototyping.
3. Unattended printing is one of the criteria for the RepRap / Kartik M. Gada Humanitarian Innovation Prize.