One nicety about Mac OS X packages (folders that look like files; they're how most applications are delivered these days) is that they make installation easy. You download a disk image, open its window if necessary, and drag the program inside to your Applications folder. What could be easier?
Well, it would be easier if your Applications folder was a readily available target, but unless you've put it in your Dock or made it permanently visible in some other way, you must somehow display it, such as by opening another window or revealing the sidebar in the disk image's window by clicking the toolbar lozenge. But what if the developer made an alias to the Applications folder right in that disk image window, such that installation becomes merely a matter of dragging the program a short distance in the same window? Particularly if there's also a bit of instructional text and a graphical indication of what to do like an arrow, such an approach would make for an even better user experience than we have now.
I had just that idea a few years ago at MacHack while chatting with MindVision's Josh Ferguson about FileStorm, which makes it easy to create classy-looking disk images. But like so many good ideas, I never looked into what was necessary to make it reality. Just the other day, though, I downloaded a beta version of Dejal Systems' server monitoring tool Simon, and was delighted to see that David Sinclair of Dejal had implemented the very same idea.
When I asked David how he'd done it, he admitted that he'd read about the technique on O'Reilly's MacDevCenter in an article by Ben Artin, who works with Jim Matthews on Fetch (and who was a regular at MacHack - clearly all roads lead to Dearborn, Michigan). You can read Ben's full article for details, but in short, the trick turns out to rely on a Unix symbolic link instead of a normal alias, since a symbolic link can stand in for the Applications folder on the system it's on, rather than being an alias to the developer's Applications folder.
If you're a developer whose software should live in the Applications folder, I encourage you to adopt this approach to simplifying the installation process for your users. And if you're a user, like me, who has been irritated at having to reveal an Applications folder icon before dragging a new program to it, a gentle suggestion to developers whose software you've purchased wouldn't be amiss.