The term CTR in case of online advertising stand for Click-through-rates. It is mostly used to understand how successful a particular advertising campaign has been. It is basically used for understanding the success of the clicked on ads and are thus used for banner ads, contextual popunder advertisement and other similar advertisement. The click through rate is calculated by dividing the number of user by the number of impressions. This means that if an ad has delivered 100 impressions or has been viewed or clicked on for 100 times by 5 users then the CTR is 5 percent. If the ad has been click on by 100 users 100 times then the success rate is 100 percent.
It is better to have a high click through rate as that reflects an effective advertisement campaigns. In order to get high CTR, it is best to advertise on websites that have a high traffic or fan following would be better as it would be noticed and can help you to get good traffic through the ad. For a good CTR, it is best to hire a company that deals with Online Media and understands online marketing well. They can design your ad campaign efficiently so that you are able to enjoy a good success rate.