When Apple came out with Mac OS X 10.6 Snow Leopard, the company unveiled a whole new version of QuickTime Player (and also jumped a couple of version numbers in the process -- going from "7" to "X," or 10). The player component of QuickTime X was much sleeker than QuickTime Player 7, but it lacked a lot of the added features that version 7 had (like Play Selection Only, Loop Back and Forth, etc). While it doesn't appear that Apple has added any of those features back into QuickTime X yet, the Lion Developer Preview 2 released today sports a new QuickTime X player (version 10.1) with additional sharing options.
In the QuickTime X player that shipped with Snow Leopard (version 10.0), Apple allowed you to share your videos right from QuickTime Player to iTunes, MobileMe or YouTube. Now, with the forthcoming player that will ship with Lion, Apple is enabling additional sharing options, including sharing with Apple's Mail.app and the websites Vimeo, Facebook and Flickr. It's nice to see Apple improving QuickTime X, and hopefully it will eventually get around to adding back all the features of QuickTime Player 7. Until then, there's always the QuickTime Player X plug-in, which adds some functionality back to the current version of QuickTime X. You can also keep a copy of the QuickTime 7 Player, which is an optional Snow Leopard install.
Apple OS X Yosemite