Google Moving to Google AdWords A Hands-On Guide for Premium Advertisers - Manual (Page 22)

Just a little more detail
Keyword matching options
Broad match. Your ad appears when the words in your keyword are contained in the
query, regardless of their order and even if other words are also included. A broad
match for the keyword
tennis shoes would include shoes for tennis and tennis dresses
and shoes. Broad matches are often best, because your ads will get more exposure.
Exact match. The search query must exactly match your keyword. So tennis shoes will
only match a user request for tennis shoes and not for red tennis shoes, even though
the second query contains your keyword.
Phrase match. Your ad appears when the user searches on the exact phrase, and also
when their search contains additional terms, as long as the keyword phrase is in exactly
the same order, with no additional words within the phrase. A phrase match for
tennis
shoes would include red tennis shoes but not shoes for tennis or tennis type shoes.
In the case of one-word keywords, there’s no difference between a broad match and a
phrase match.
Negative keywords. Negative keywords enable you to eliminate searches that are not
related to your message. If you add the negative keyword -table to your keyword tennis
shoes, your ad will not appear when a user searches on table tennis shoes. Negative
keywords should be used with caution: if applied incorrectly, they can eliminate large
portions of a desired audience. Your Google account team can help you set up negative
keywords effectively.
Disabled keywords
At Google, we want our users to enjoy relevant search results and relevant ads. Since
CTR is our best measure of relevance and effectiveness, we look at your CTR after
every 1,000 impressions. At that time, we may disable keywords if the CTR on Google
is less than 0.5 percent. In addition, if the CTR for your account is less than 0.5
percent, we may slow delivery of impressions to give you and your account team the
opportunity to optimize your keywords and creative for better results. To prevent re-
insertion of poorly performing keywords, the performance history of your keywords is
saved to your account. It’s important, therefore, to invest time in developing the right
keywords before you begin.
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