As a part of making the debut “Meet the MakerBot Operator” profile video, I worked with the Nick and Winter to co-create the “MakerBot Operators Tips” video released here.
When downloading objects from ;Thingiverse.com, Nick and Winter take time to repair manifold (“water-tightness”) issues with models before feeding them into Skeinforge to create printable gcode. Skeinforge takes an .stl file, an abstract representation for a volume, and interprets the linear printable path that will allow the MakerBot to print it. While any number of CAD and 3D design tools can export .stl files at the end of the chain, unless the object is manifold/“water-tight” (separating the surface from the interior volume it contains) it is difficult for Skeinforge to trace a linear path.
After Nick and Winter fix the model to make it well and truly manifold, they take the time to re-post the fix back to Thingiverse as a derivative to help others print the object more easily. This is, in my opinion at least, a pretty awesome community service that helps everyone print objects more easily.