Design driven by lawsuits
First off, just for fun.
This totally needs to be on a t-shirt. I would buy it in a heartbeat.
If you're the kind of person who still uses IE and you've noticed that things are starting behave weirdly today, you've just been given another reason to switch to Firefox.
Microsoft is in a patent lawsuit, and today they released a "patch" to ActiveX, which basically breaks every embedded player for Flash, QuickTime, WinMedia, etc.
The ActiveX update makes a very simple change. It prevents you from automatically interacting with an embedded object - like a flash movie. You have to activate it first.
In general, and contrary to what many people have speculated, it only prevents interaction with embedded content. If you add a flash movie to your site, it will play, but you cannot interact with it. That includes any mouseOver effects.
This was supposed to go out in June 2006, but it was released today with very little fanfare.
Safari, Opera, and Firefox users remain unaffected by these shenanigans.