Carousels are a popular UI element. Unlike other elements that are often constrained by the main view, they often occupy the entire width of a page (the viewport), as can be seen from the following examples.
Update: you can now download the jQuery plugin for embedding YouTube videos with high quality thumbnail here.
Have you come across this problem? You want to embed a YouTube video to your website. The video itself is HD. However, once you embed it, its thumbnail becomes low-res and blurry, like the YouTube video below.