Up until a couple days ago I had no problem viewing videos on YouTube, but now I can’t seem to download more than about 10 seconds worth of one, which takes several minutes, before it “ends” and the “share” and “watch again” buttons come up. Another odd thing is that the other movie links that usually appear under those buttons flash rapidly, instead of the steady images I’ve always had before. I can still stream videos from other sites np with my cable modem, e.g. Google videos. Also something at the bottom of the page “Read sjl-static…” is flashing quickly as well. I’ve downloaded and installed the required flashplayer again, but that didn’t help. Anyone have a suggestion?
Try clearing your cache and cookies then rebooting.
Done, no improvement though. Another peculiar symptom: it is taking forever for YouTube’s homepage to load. No other sites giving me this problem, not even SDMB at the moment. 
Do you use DSL for internet access? I had a similar problem with slow web browsing, but I did the “power cycle” and it worked for me.
Here is the AT&T page on problem shooting:
http://support.sbcglobal.net/article.php?item=2