Enhancing functionality
Potentially more significant, Apple has finally decided to do something that other browsers have been doing for years and allow Safari's functionality to be enhanced with extensions that can be run on the Windows and Mac versions.
Right now, this infrastructure isn't even enabled by default - to turn it on, you have to go by the circuitous route of turning on Safari's menu bar, enabling its Develop menu and turning on Extensions there. That's most likely because Apple sprung the feature on developers at its recent conference, so it isn't yet ready to launch its public Extensions Gallery. That will open later in the summer to showcase the growing library of officially signed (but free to develop) extensions.
That should bring some genuinely useful tools, since eager beavers swiftly got to work within days of Safari 5's release. An index of examples can be found at safariextensions.tumblr.com, among which you'll find an Amazon.com search bar, a basic URL shortener and a tool that dims all page content except for the video you're watching.
No matter how long it has taken, it's a great move that makes Safari a more appealing alternative, not to mention a more realistic one if you've stuck with Firefox until now for this capability. It's still early days, though, and Safari has years of catching up to do.
Developers don't need to buy a Mac or any development tools to make extensions. As with other browsers, they require a good command of HTML, CSS and JavaScript, and the tools to package them up for distribution are built right into the browser. When it comes to security, they're sand-boxed from the rest of the browser, a common theme with browsers these days, which Apple began to address with the release of Snow Leopard, on which the Flash Player plug-in is isolated to reduce the risk of it taking down the browser.
