When you post a link in Facebook, Facebook scans the page that you’re posting and looks for certain tags to tell it what the links is about. Unless you’ve setup your site with special markup, however, Facebook will just grab the page’s title and the first paragraph or two of the pages content, and possibly a random image. If you want to control this you need to add special markup.
Below is a sample of how to post a video:
<meta name="title" content="Neil Michelin's Huge Muskie" /> <meta name="description" content="Neil talks about catching his personal best, a fish nearing the 60" mark, while Muskie fishing August second, 2008 on Lac Seul tossing a Shumway Flasher." /> <link rel="image_src" href="http://video.outdoorsfirst.com/159c6604-219b-441a-be7c-c86f56a4fe2c.wmv.jpg" /> <link rel="video_src" href="http://upload.outdoorsfirst.com/flash/video2.2_med.swf?ad=http://video.outdoorsfirst.com/slug_toyota.flv&atitle=Advertisement&video=http://video.outdoorsfirst.com/159c6604-219b-441a-be7c-c86f56a4fe2c.wmv.flv&btitle=Neil Michelin's Huge Muskie&ref=fb"/> <meta name="video_height" content="387" /> <meta name="video_width" content="486" /> <meta name="video_type" content="application/x-shockwave-flash" />