I imagine this has something to do with an idea like "on exit frame"??? thats my best guess, im completely lost on this one and i NEED this effect, with all the work to transition in, it only makes sense to transition out.
From what I can see the other 2 sites don't have any out transitions. They just CUT to a blank and then animate in regardless of where you're currently at. That is the simpler trend. On your site it's actually more complex in that your links do animate out and then the new page animates in. Tell you the truth, watching any of this stuff animate in and out bugs the hell out of me when I'm trying to get information. And that's what the web is all about. So how do I bookmark one of the sub pages/links on your site? I can't. All I can bookmark is your home page. Then I'm forced to navigate through all the effects I've already seen. Something to think over. Somewhere there's a happy medium with the use of flash. I tend to think the better use is with elements on a page. Not a whole site. Google can't read or index one single word of your flash site either. So it all depends on who your audience is and what their needs are.