It would be fantastic to be able to include/drag Mac OS Smart Folders in(to) the backup sets. This search method could really provide a way to backup and/or exclude very specific items.
Scenario: I use iTunes Movie Rentals and each movie download is usually well over 1 GB. Using Smart Folders I can build a 'folder' that isolates this or any downloaded movie rental file for exclusion automatically. I could then drag this Smart Folder into the Mozy backup sets and exclude it...o massive backup for a very temporary file!