AdWords (Google AdWords) is an advertising service by Google for businesses wanting to display ads on Google and its advertising network. The AdWords program enables businesses to set a budget for advertising and only pay when people click the ads. The ad service is largely focused on keywords.
Businesses that use AdWords can create relevant ads using keywords that people who search the Web using the Google search engine would use. The keyword, when searched for triggers your ad to be shown. AdWords at the top ads that appear under the heading "Sponsored Links" found on the right-hand side or above Google search results. If your AdWords ad is clicked on, Google search users are then directed to your website.

When choosing keywords for your AdWords campaigns different matching options are available. The two main keyword match options include the following:
                •    Broad Match: This reaches the most users by showing your ad whenever your keyword is searched for.
                •    Negative Match: This option prevents your ad from showing when a word or phrase you specify is searched for.
                •    Phrase Match: Your ad is shown for searches that match the exact phrase.
                •    Exact Match: Your ad is shown for searches that match the exact phrase exclusively.

 

Pay per click (PPC) (also called Cost per click) is an Internet advertising model used to direct traffic to websites, where advertisers pay the publisher (typically a website owner) when the ad is clicked. With search engines, advertisers typically bid on keyword phrases relevant to their target market. Content sites commonly charge a fixed price per click rather than use a bidding system. PPC "display" advertisements are shown on web sites with related content that have agreed to show ads. This approach differs from the "pay per impression" methods used in television and newspaper advertising.
In contrast to the generalized portal, which seeks to drive a high volume of traffic to one site, PPC implements the so-called affiliate model, that provides purchase opportunities wherever people may be surfing. It does this by offering financial incentives (in the form of a percentage of revenue) to affiliated partner sites. The affiliates provide purchase-point click-through to the merchant. It is a pay-for-performance model: If an affiliate does not generate sales, it represents no cost to the merchant. Variations include banner exchange, pay-per-click, and revenue sharing programs.