Tagging is the 'in thing', enabling you to group, catalogue and cross-reference items via keywords so you don't have to store them together. Particularly popular on sites such as Flickr, Tags brings robust tagging to Mac OS X.
The Tags interface is split into two components; a system-wide floating window triggered by a hotkey and the Tag Manager.
On making a selection in a supported application, you type comma-separated tags, or choose from recent tags or favourites.
On 'flipping' the window to search mode, defined tags are used to retrieve and filter a list matching your query. The Tag Manager enables tags to be edited, flagged as favourites, and sent to Finder's sidebar as Smart Folders.
Application support is strong; Mail, iPhoto, Safari, Finder, Microsoft Office and Address Book work nicely with Tags, but iCal and Firefox don't. However, the interface could be improved. The Tag Manager is clunky – the Favorite box isn't apparent and the inability to access Quick Look via the [Spacebar] is baffling.
Despite these minor misgivings and an optimistic price-point, Tags is worthy of consideration. It's good for drawing together information for projects, without physically collecting files together, and as more apps take advantage of the OpenMeta tagging standard, Tags could become a Mac essential.