Safari won't show youtube videos

You need RealPlayer X for Mac:

http://forms.real.com/real/player/blackjack.html?platform2=Mac%20OS%20X&product= RealPlayer%2010&proc=g3&lang=&show_list=0&src=macjack

No.
They need Flash Player to view YouTube files.
Free from Adobe.
After installing Flash Player 9 if you still have the ? on the page please search through the QuickTime Discussions pages for the fix (MIME Settings adjustments).

Thanks QTKirk, I stand corrected. 🙂

I don't visit the "tube" and could care less what they offer.
But the files are Flash Video using Spark 2 (I think) and each of them started out as something other than Flash Video.
YouTube uses special software to "convert" every upload to Flash Video. That's why they look like junk in most cases.
I'll stick with QuickTime for file size and quality video.

I don't visit the "tube" and could care less what they offer.

Agreed. Nor me. Unless someone gives me a link because there is something they want me to see, and they always play fine for me.

I wonder how!

Have you got plugins enabled in Safari's preferences??

Been there done all this -- previous (closed) topic on same issue said to disable Flashplayer in MIME Settings. Did this and it worked for a few days, but now back to same pb. And BTW EWHY the f* do they play OK in Firefox??? This is definitely an APPLE bug; have sent innumerable Bug Reports to them, to no avail 😟

Remove the check mark for Flash Video (MIME Settings / Miscellaneous) so QuickTime plug-in doesn't try and play them.
Quit and relaunch Safari.

I remember I downloaded Flash Player for the Youtube videos. But certain ones might need Real Player X. I downloaded both just to be one the safe side. After you download them, restart Safari or Restart you computer