It's the most infamous of the applications that have been left behind by the latest version of the Mac operating system, which no longer runs apps written for the PowerPC architecture, as Quicken 2007 was. And if you upgraded to OS X Lion, Quicken 2007 will no longer work on your Mac. There's Quicken 2007 for the Mac, but nothing serious after that. If you're on a Mac, though, you might think Intuit has abandoned you.
If you have a grown-up financial life, with money in investment vehicles, Intuit has an up-to-date version of Quicken to help you keep track of it all-on Windows.