Yet another reason to include video on your website or blog, specifically YouTube videos. Now, when you embed a YouTube video, you'll see a search bar appear at the top of the video, when moused-over and at the video's conclusion. Users can then search and watch other YouTube videos without ever leaving your site or blog post. And when users stay put, you get a higher time-on-site metric.
For publishers, this means you could see more time to engage your visitors, and possibly become more attractive to advertisers. If you embed videos frequently, consider reserving some prime real estate for advertisers right next to your embeds.
For advertisers, this can be a mixed bag. On the one hand, you might get longer exposure for your ad. On the other, user engagement statistics could be inflated. And, unless your ad is positioned next to videos, you might be paying a premium for eyeballs that aren't really there.
Some have complained that the search bar is unattractive and takes up too much screen space (especially for smaller embedded videos.) You can remove the search bar by adding &showsearch=0 to the embed code.