Thanks to Bonjour, it’s a lot easier to connect to printers, servers, other computers, and other devices over a network. Originally introduced in 2002 as Rendezvous in Mac OS X 10.2 and renamed Bonjour with the 2005 release of Tiger, Bonjour is Apple’s version of the Zero Configuration Networking (Zeroconf) technology. When devices on a network are using Bonjour, there’s no need to mess with confusing network settings and controls. Bonjour devices automatically make themselves available on the network, and the technology resolves any addressing issues for you.

Bonjour has a wide variety of implementations; it can be used to connect your Mac to a printer, or you can connect to another Mac to share files. There’s even a Windows version of Bonjour, so your Mac can connect to a Windows PC. Software programs like iChat and iPhoto can use Bonjour, too—the most common software use of Bonjour is in iTunes. When you connect someone who’s sharing their music, you’re witnessing Bonjour at work.—ROMAN LOYOLA

Smart Folders

The Finder evolved as a way to put a friendly face on the scary world of computer file systems, but as the way we’ve used computers has evolved, our file systems have gotten out of control. Smart Folders (and its cousin, Smart Mailboxes) was Apple’s way of letting users tease order out of an unruly set of personal files. Using the power of the Spotlight search engine (also added as a part of Mac OS X 10.4), Smart Folders are essentially saved searches. Tell your Mac that you want to see all the Word files you’ve created in the past 10 days, and boom, there’s a folder full of those files. For many users, Smart Folders make it okay to toss all your stuff in one big folder rather than using a complex, folder-based filing system. After all, Smart Folders can do the organization for you.—JASON SNELL

Also Worth a Mention

Limiting yourself to just 10 noteworthy features for something as complex as Mac OS X means you’re going to wind up with some noteworthy omissions. We had several features that just missed making our list, including the Dock (and its clever way of keeping the applications you need close at hand) and Automator (which demystified script-writing for most users). We’re also fans of Quick Look, one of OS X’s best time-saving features for getting a glimpse of a file with a simple stroke of the space bar. And we debated including OS X’s support for Intel-built processors as well.

But that’s just our list of OS X features worth celebrating on this anniversary. We’re sure we’ve overlooked a couple of your favorites; let us know what’s on your list of OS X’s greatest contributions.