Smarts is a Smart Playlist Manager
Smarts will save and store the criteria of an iTunes Smart Playlist -- the "smarts" of a Smart Playlist -- as a template so you can reload it into iTunes later.
• Use Smart Playlist "Starter" Templates •
Perhaps the best use of Smarts is to maintain several "starter" Smart Playlist templates of your frequently used criteria (eg: Genre is not Holiday or Last Played is not in the last 6 months). Instead of painstakingly re-entering the same basic -- and perhaps elaborate -- criteria over and over again, just load a pre-made "starter" template as a new Smart Playlist in iTunes. Smarts can even open the Smart Playlist Edit window for you automatically after the template is loaded so you can easily provide additional criteria. (Smart Playlist criteria can only be edited in iTunes.)
• Reduce the Number of Active Smart Playlists •
iTunes performance is smoother when there are fewer active Smart Playlists to continuously maintain. With the criteria of your Smart Playlists saved as templates in Smarts you can safely remove unused Smart Playlists from iTunes and then restore them from the templates only when you want to use them again.
• Keep Notes on Templates •
You can enter a little bit of info for each template to help describe the template beyond just its name.
• Export Smart Playlist XML files •
Saved Smart Playlist templates can be individually exported as XML files which can be backed-up or shared with other iTunes users (specific track information, however, is not exported -- only the criteria). Smart Playlist XML files exported by Smarts can be imported to iTunes using the iTunes "Import Playlist..." command.