It can be really annoying to go to a site and be welcome with this loud video that suddenly prompts you to lower the volume because you don't want your boss to realise that you're visiting 'non work' related sites. Video ads in particular can irritate a visitor and cause them to never return to your site.

Strangely enough, if you were to autorun an embedded video ad after most of the page content is loaded and to make sure that the video has NO AUDIO, nothing much happens. No irritation, no leaving the site, just browsing as usual (provided the video doesn't suck too much of the bandwidth-small videos)

Ofcourse, it becomes something more like a flashbanner, but visually more appealing and eye-catching. You'll also need to come up with a method to communicate your marketing message.