Tags allows you to manage all your files so that you can easily find the files that you need, when you need them.
Tag everything on your Mac: documents, emails, images and all other files. Quickly find files irrespective of where you saved them. You can bring up the Tag's UI with a simple keystroke in most applications, so that you can Tag files and search for Tags, wherever you are.
Tags are like keywords for files. Using tags allows you to group files which have something in common. You can apply many different Tags to a single file as well as apply the same Tag to multiple files. This allows you to associate files to one another in a way far superior to a rigid file / folder structure.
Features:
Tag Files directly in all supported applications
Full Spotlight Integration
Supports in application search
Create smart folders and mailboxes
Applescript support
Supported Applications:
Tags works natively with basically all applications that properly support applescript.
Finder
Mail
Address Book
iPhoto
Safari
Microsoft Office (Word, Excel etc.)
Adobe Photoshop
Xcode
RapidWeaver
OmniOutliner
Pages
Keynote
Quicktime
Of course, even if the App is not supported, you can still always tag the resulting file in the Finder!
WHAT'S NEW
Version 1.3:
Snow Leopard Support
Performance and Stability improvements