A lot of people are so fed up with Flash that they use software to block all Flash objects by default. These people probably do not need this script. This script is for people who are okay with seeing Flash the odd time but not okay with Youtube videos embedded on other sites. This is inferior to watching the video on the actual Youtube site for many reasons:
1. On Youtube, one video renders at a time. You don't have to wait for a page that has 20 embedded videos when you only want to watch one.
2. When you are on the Youtube site, video download extensions recognize this and offer you the chance to download the video.
3. Lots of embedded Youtube videos appear on blogs where the blogger has gone to great lengths to make sure the element's size looks good on his or her site. This usually means you have no control over the resolution of the video you're watching like you would on Youtube.
Some one who recognizes these limitations should be able to go to Youtube as an easy alternative, but even this is not so easy. The containers for embedded Youtube videos do not function as links! Clicking the video makes it start playing and does not take your browser anywhere. Right clicking the video obviously doesn't help (because it's Flash) and clicking that title bar at the top usually takes you to a page that tries to make the video play in fullscreen mode without even asking you if this is what you want! Normally, to opt-out of watching an embedded Youtube video, one has to wait for the video to render anyway, view the page source, find the URL of the Youtube video in there and then paste that into the browser's address bar. This is absurd! Say no to embedded Youtube videos by replacing them with simple links!