I'm not having quite the same problem on my Mac, Genie, but constantly have problems with YouTube(and other videos) and Safari.

Anything that uses Flashplayer is prone to cause Safari to crash (doesn't happen with Firefox.)

Also have problems with Java and/or javascripts - too illiterate to sort that one out. Anyway - won't update and on a lot of sites (but not Youtube,) I get the coffee cup icon where there should be content.

And I am now thinking this is serious thread-drift. If anyone understands my gibberish and is inclined to pm with advise, please do so.