As I can personally attest, one can lose hours of productivity to YouTube and Wikipedia. These two sites, however can provide a wealth of information for research purposes. If you agree with my assessment, then you might enjoy Chrome extension WikiTube, which embeds YouTube videos at the top of Wikipedia pages.
After installing the extension, the next time you open a Wikipedia page on a particular topic, you'll see a belt at the top of the page with three embedded YouTube videos. You can play the videos right from the Wikipedia page, which helps when you are embroiled in a research effort that has spawned dozens upon dozens of browser tabs and windows. And if you scroll to the right of the YouTube video belt, a red "+" button will appear, which when clicked will load another three videos to the belt.
(Via Lifehacker)