One of my favorite aspects of mac OS X is the availability of smart folders. It took me a little while to really begin to find them useful, but now that I've gotten more comfortable with them smart folders are an integral part of the way I use my mac.
Really, a smart folder is nothing more than a saved search. Imagine having your computer search for a certain type of file that meets a certain set of criteria, then having it remember that search and automatically update it as files are created, manipulated and deleted. That's a smart folder.
Lets say I want a smart folder that contains all the presentations I've created for my job. I open a new finder window and choose File -> New Smart Folder. A window appears asking me to set some criteria for my new smart folder and I tell it to include items with the Kind -> Presentations. This lets the smart folder know that I want it to contain only items that are Keynote or PowerPoint presentations. Then I set the next set of criteria to Contents -> "Grace". This tells the smart folder that, not only do I only want presentations, but only presentations that contain the word "Grace". The name of my employer includes the word "Grace" so this should narrow the smart folder contents down to only presentations that concern my job.
I could set more criteria by hitting the "+" button on the right, but for now I'll just stick with these two. I select the "save" button in the upper right and give my new smart folder a name. In this case I've chosen "Work Presentations".
I hit "ok" and viola! A new smart folder pops up in the sidebar. From this moment on every presentation that contains the word "Grace" will be automatically added to this folder.
Smart folders can be nice in the finder, but I find them especially useful for organizing data in other applications like Mail, iPhoto or iTunes. In fact, I hardly use regular folders in Mail anymore at all, just smart folders. Here's a screenshot of my folder structure
As you can see, I only have two normal folders. When a new message arrives it's automatically sent into either "In the Book" or "Not in the Book" depending on whether the sender is in my address book or not. My smart folders then keep tabs on all the messages contained in those folders and organize them for me. One smart folder collects all my flagged messages, another collects all the messages from co-workers or customers, another collects all the bills, receipts and banking related messages, and so on.
It took a little tweaking to get all the smart folder criteria right, but it was well worth it. Now my mail sorts itself automatically, and unlike using mail rules the same message can be sorted into multiple categories without creating multiple copies.I also use smart folders extensively in iTunes and iPhoto, but I'll save those details for a later post specific to those applications. How do you use smart folders? Feel free to post your most useful smart folder ideas.