When setting up a PPC campaign in Google Adwords , keyword matching determines how the keywords or keyword phrases you're advertising for will be served up. There are four types of keyword matching:

• Broad Match – as the name implies, this is the broadest possible kind of keyword match.
• Phrase Match – this option narrows the results down from a broad match
• Exact Match – this is the most precisely defined kind of match
• Negative Keyword – determines the which keywords will not be included in the search results

For a full explanation, visit the Google Adwords Help Center .

Proper use of keyword matching has the potential to make an ad campaign much more effective by generating more qualified traffic; although, using more restrictive types of keyword matching may reduce the total number of ad clicks dramatically. Consequently, it's essential to be clear on your objectives going into the campaign so you can make the right choices about keyword matching.