As far as Google AdWords is concerned, a click happens when someone sees your Pay per Click ad and clicks on it. An impression occurs when someone enters one of your search terms into the search engine, and your ad appears.
This difference is crucial as you aren’t charged for an impression, even though the person searching the internet may have seen the ad. You are only charged for actual clicks. If you are targeting the right keywords, and your advert is correctly worded leaving potential visitors in no doubt about what you offer, this means that you can be sure the people clicking through to your site are interested in your product or service. You already know they were searching for one of your keywords, and as your ad explains it further, effectively your site has less work to do to convert that visitor to a customer.
Even though you only pay for each click through (Cost Per Click), it is important to keep track of the number of impressions, as well as the number of clicks. If you have a consistently high number of impressions with a low number of clicks, you may need to rethink the wording or placement of your ads. Adjusting the time of day it appears, specifying a longer keyphrase, or rewording your ads can help boost the click to impression ratio.
