Landing pages compliment and reinforce online advertising by providing arriving visitors with a page that is related specifically to the ad campaign or search term advertised. This is more effective at retaining and converting visitors than sending them directly to your home page.
For Pay Per Click (PPC) campaigns, a landing page on your site is meant to be about the keyphrases that you are bidding on so that visitors are less likely to hit the “back button” as soon as they get to your site, and are more likely to order your products.
Landing pages can also be created to focus on specific products or services that you offer in order to draw organic search results to it. Thus they become a landing page for organic results as well.