From: »
www.neogaf.com/forum/sho ··· t=797609Short story, if you copy a URL ending in .webm, the forum turns it into an inline clip (assuming the resource actually *is* a webm file).
webm is an HTML5 wrapped video format that usually uses VP8 encoded video which is similar but not quite as nice as H264, but not encumbered by patents (google released the code for it).
The advantages over animated gifs (and inline flash video) is that it is much faster to load it plays almost immediately. The disadvantages for this simple substitution of link to inline video element is that I've not added any neat control of size etc.
It will play out of the box on Chrome, firefox, Opera -- but not Safari and not mobile either. For mobile, the clips will just show as links that are useless unless your phone has a custom browser or plugin.