However, Facebook's long-press function makes sense inside an app. It's less a webapp there, and more a desktop app--even though it's interfacing with the Inter

However, Facebook's long-press function makes sense inside an app. It's less a webapp there, and more a desktop app--even though it's interfacing with the Internet, it's presented standalone, not as a place to go within another program. You don't expect to see the browser's long-press menu in the Facebook app, because there is no browser. As for desktop, if they're intelligent at all, they'll use a different method there. Perhaps all the new variations will be displayed side by side. Perhaps instead of only trigfering on a "long-click", it'll expand on a normal click.