1. The First Gate: Impressions and CTR

When YouTube's Recommendation Engine "tests" your video, it serves it as an "impression" on users' homepages, in suggested video sidebars, and on other browse features. Every time your thumbnail appears on someone's screen, that's one impression. CTR is the ratio of clicks to impressions. If your video gets 1,000 impressions and 100 people click on it, you have a CTR of 10%. YouTube says typical CTRs fall roughly between 2% and 10% depending on the channel and traffic source, so compare each video to your own channel average rather than a fixed target. A high CTR is the "first gate" your video must pass through to achieve viral reach.