Mac OS X includes a powerful search technology called Spotlight, which you can use to find just about anything on your Mac. With Personal Backup X5, we have added a way to back up Spotlight searches dynamically. This means that each backup will copy the files that match your search criteria at the time you run the backup. This is not a static selection of files, but rather one that updates as you work on your Mac.
To do this, create a new backup script, and, for its source, select Spotlight Search from the Kind menu: you’ll see a sheet where you can set up a Spotlight search.

To create a search, first choose a location from the Search in menu. This can be Computer (your Mac), Home Folder (your home folder) or other. If you choose other, you can select any folder or volume you would like to search.
Next, choose criteria for your search. For example, you could choose Content Modified from the first menu, then After from the second menu, and enter a date in the text field. Or you could choose a specific type of file (Kind > Contains > Word to find all Microsoft Word documents). For more on using Spotlight to create searches, see Mac OS X’s help documentation.
Note that you can also drag a smart folder, which is a way of saving a Spotlight Search, from the Finder onto the Source section of the Personal Backup X5 window to add that search as a source. If the smart folder is in the Finder sidebar, click the folder, then drag its “proxy” icon—the icon in the title bar of the window—onto the Source section of the Personal Backup X5 window.