Always put a rel=0 attribute on Youtube embedded videos so that related videos aren't shown at the end

strip_related_videos.php

// Jay Caines-Gooby, 2011
// @jaygooby on twitter
// [email protected]
//
// Put this in your theme's functions.php file
// and any Youtube videos you embed by putting the 'watch' url on a line
// on it's own in a post or page won't get related videos shown at
// the end of the video.

// The 10 & 3 args here are the priority of the filter (10 is default)
// and the 3 is the number of arguments that the filter function takes
add_filter('oembed_dataparse','strip_related_videos',10,3);

function strip_related_videos($return, $data, $url) {
    if ($data->provider_name == 'YouTube') {
        $data->html = str_replace('feature=oembed', 'feature=oembed&rel=0', $data->html);
        return $data->html;
    } else return $return;
}

Thanks for that.. If might suggest one thing, then I would mention that the code "oembed_dataparse" runs before the content is cached
this: "embed_oembed_html" does it after it is rendered to the page. I think it is wort to mention that, otherwise people might think the code doesn't work