In Google AdWords you need to abide by a particular ad structure with requirements for how many characters can appear in an ad:
|Ad Section||Length in Characters|
|Ad Title or Ad Headline||25 with spaces.|
|Description Line 1||35 with spaces.|
|Description Line 2||35 with spaces.|
|Display URL||35 with spaces.|
|Destination URL||1024 with spaces|
Only the first four elements listed above will be displayed to the user. The display URL is simply the Web address users see when they view your ad. Destination URL is where users land when they click your ad and it is not visible in the ad. Display URL and destination URL don't have to be the same. However, a display URL must be an actual URL for your site.
Here is an example from Google, in whichi each of the following ads is intended to sell more gourmet coffee beans.
Let's analyze the ads shown in example 1:
|Headline focuses on company's brand name which does not have strong brand equity.||Headline focuses on the specific offering and core selling points.|
|No key words in the headline.||Headline contains relevant keywords.|
|Generic description, no call to action.||Description has call to action (buy now) and has product differentiator line (e.g., specialty blends).|
|Landing page is just the home page.||Landing page is specific to gourmet coffee.|