Lock-in is stupid and so are you for wanting it

If you think trying to lock-in your users to your platform is a good idea, you're an idiot.

People use your products out of courtesy and respect, not out of obligation. Trying to force them to continue using your products is, as Cory Doctorow once said, a drug dealer's business model. And not one you want to emulate if you run a more respectable business.

So if you have videos on your site that require a Windows/Mac plugin that requires the newest version (or even those two operating systems), you're being stupid. At least allow someone who's running something else to download the actual video file.

If I can't view your video because I don't have the latest version of the software, or because it requires Windows, I'm not going to upgrade immediately or change. I'm going to forget about the video. I'm going to discredit your site.

And I'm going to discredit the operating system/plugin you require.