Pay per click (PPC) is an advertising model used on search engines, advertising networks, websites or blogs. Advertisers only pay when a user clicks on an ad to visit the advertiser’s website.

Advertisers bid on keywords that will be used as search terms when they are looking for a product or service. When a user types a keyword query matching the advertiser’s keyword list, or views a page with relevant content, the advertiser’s ad may be shown.

These ads are called a “Sponsored link” or “sponsored ads” and appear on search engine results pages, or anywhere a webmaster or blogger chooses on a content page.

Picked and edited from Wikipedia.