Click-through rate (CTR) is a metric that measures how often people click on a link compared to how many times it was shown. For example, if a website displays an advertisement 100 times and 5 people click on it, the CTR would be 5%. A higher CTR indicates that the content is engaging and relevant to the audience. Businesses and marketers use CTR to evaluate the effectiveness of their online campaigns. By analyzing CTR, they can determine which ads or emails resonate with their audience and make adjustments to improve performance. A good CTR can lead to increased traffic and better conversion rates.