As we love web standards, we did not use the code that Youtube offers for embedding videos. This code contains the embed tag which is non-standard and does not validate as xhtml. If you want to embed a youtube video in your blog or site use this
<object type="application/x-shockwave-flash" data="http://www.youtube.com/v/moviecode" width="400" height="326"><param name="movie" value="http://www.youtube.com/v/moviecode" /></object>
The moviecode is a code found in each youtube video adress and is after v= until the first ampersand (&). For example in this URL http://www.youtube.com/watch?v=xmHHjUZPyMY, the code is xmHHjUZPyMY. Using this code Typpz blog is still using valid XHTML.