Adwords
It is a Pay Per Click advertising program from Google. Your ads will show either on the google websites, affiliate or you can choose for them to display on the 'display network' which are any websites that show google ads (also known as adsense).
On the Display network, you don't just have to have text ads, you can also have images, videos and others. You can also choose to have specialised mobile ads which display a little differently on phones and other mobile devices.
