Wow, almost all of the applications mentioned here are of the multi-user, hosted in your local intranet, "enterprise" variety. These applications do seem to be

Wow, almost all of the applications mentioned here are of the multi-user, hosted in your local intranet, "enterprise" variety. These applications do seem to be particularly problematic - the combination of being customizable, multi-user, with complicated permissioning models, and allowing users to store content in the application without a storage quota or garbage collection mechanism model leads to the same obvious problems time and time again.