Once a mesh has been skinned, making geometry changes can be a pain, as weights often have to be redone in some way or another. Weight transfer scripts have traditionally relied on proximity based or vertex index based import/exporting of weights. These methods both have big weak points. Vertex indicies change when topology changes are made, and proximity based weight transfers are prone to error, especially when topology changes drastically. zooWeightSave works using a different method of weight transfer.
zooWeightSave stores a mesh's skin weight data into the mesh itself using blind data. Blind data gets stored on the verticies themselves, and are thus immune to geometry modifications that alter vertex indicies. Once blind data has been applied to a vertex, it becomes information stored with that vertex. So if the vertex's index changes, it doesn't matter, as the information is part of the vertex itself.
Additionally, the weights are saved with the mesh, instead of in a separate file, so it makes saving weights much easier than having to remember where the weights file was stored.
v1.1.1 Sorry the last upload didn't work properly. Has now been fixed.