When your website shows in the organic (unpaid) results, the description of your website is often the meta tag description from your home page. This is the same description unless you have updated the page on your website and Google has discovered the change. You do not directly control those descriptions and it is the same description regardless of the search, a situation that can be improved.

Suppose a travel agent has a name and meta description such as-
“We specialize in Cruise vacations for families and couples. We represent all major cruise lines and have the lowest rates.”

This is pretty general and if I am searching for “cruise vacations” I might click it – if it were in the top results. However there will be LOTS of competition for those general terms and the people who do those searches are less likely to buy than  those doing more specific searches.

If I searched for “manassas travel agent for bahama cruise” and one of the results said ” Manassas Cruise Agent, We specialize in Bahama Cruises” then this more specific headline would earn my click over the more general description.

An ad campaign allows you to have a more specific and relevant headline than organic page descriptions. When you search on Google, the listings shown at the top and on the side are paid ads. You can determine which ads are shown for each keyword search. Your headline and message can vary according to the keyword search to make your ad more relevant.