As reported on LifeHacker.
by Whitson Gordon
Chrome/Firefox: Ever start to watch a long YouTube video, only to come back later and completely lose your place? Video Resumer is a simple extension that will remember where you stopped and pick up those videos where you left off.
Video Resumer takes almost no setup. Just install the plugin to Chrome or Firefox and start watching videos. If you stop one in the middle then leave the page, it’ll remember your place the next time you come back, so you can pick up right where you left off. It literally requires no other interaction. Hit the link to try it out.
Video Resumer (Free) | Chrome Web Store
Video Resumer (Free) | Firefox Add-Ons via GHacks