What steps will reproduce the problem?
1. Notice the strange characters on the video http://www.khanacademy.org/video/2-ln-x--x--antiderivative-example?playlist=Calculus
2. Click to view the YouTube video page and notice it is an integral symbol
What is the expected output? What do you see instead?
The same character per character description (and title or any other data ported from YouTube).
Please use labels and text to provide additional information.
This is an encoding incompatibility.
KA specifies the charset of "iso-8859-1" in a <meta> tag, but binary values (it's a multibyte code point) are not encoded as such.
The YouTube page doesn't specify a charset in the <head> anywhere except for some *.js include, however the Content-Type response parameter says it's charset is utf-8. The response header from the KA indicates UTF-8 as well, but I think the <meta> tag in the HTML is overriding it.
Tested using Chrome and Firefox, same rendering. I can provide versions if necessary.
Solution would seem to be to either (1) switch to UTF-8 either by removing the <meta> tag like YouTube or changing the <meta> tag to specify utf-8 instead of iso-8859-1 OR (2) re-encode all characters in 8859-1.