Google ad words are ads normally placed on the right side of googles search pages. Once a user searches on a particular subject or product type, they are faced with 10-12 adwords, at this stage this will be known as an impression, once a potential customer clicks on an ad a website will appear, this is known as a click which you will be charged for, (PPC is price per click).If you have 10 potential customers looking at a particular product/search page and only one customer clicks an add this gives a CTR (click through rate) of 10%

How did google become popular and effective?

Some 8 years ago half a dozen search engines come on the scene, I believe that google was the first search engine to under stand English and other languages to the extent that it does, thus providing the best search results and becoming very popular, It is estimated that 83% of all searches online are through Googles or one of Google’s partners.