:Indeed. As documented in WP:EL we avoid external linking to content which should be in Wikipedia itself.  Unfortunately most video formats are encoumbered by patents for both encoding and decoding.  We accept Ogg/Theora videos on Wikipedia, because Theora is the only current state of the art codec which is substantially free of patent problems.  The downside of Theora is that Windows and Mac systems do not support it out of the box (much as was the case for Mpeg4 or other formats just a couple of years ago). Instructions for these formats can be found on our Wikipedia:Media help page.  In the next couple of months we will enable an inline player which should greatly increase the accessability of these files.