Negative keywords are an interesting and very useful tool used to prevent certain people from accidentally coming across a site due to confusing or overlapping keywords in paid search marketing. There are many words that apply to two or more subjects, and using negative keywords can help separate and distinguish them from each other.
For example, imagine a fancy restaurant in Athens, Georgia, wants to have an informative and useful web site that attracts a lot of visitors and draws them to eat there. A common search would probably be “fine Athens dining.” However, the restaurant probably gets a lot of useless traffic from people looking for dining in Athens, Greece. Similarly, the restaurant probably loses a lot of potential traffic to restaurants in another country.
This problem can be remedied by the use of negative keywords. Unlike normal keywords, these don’t attract search engine attention. In fact, negative keywords tell search engines not to register a site under search.
In the previous example, the restaurant in Georgia could probably have added negative keywords such as –Greece, -Greek, and –Mediterranean. In doing so, it would avoid being listed in searches such as “restaurants in Athens, Greece” or “fine Mediterranean dining in Athens.”
Likewise, restaurants in Greece could include negative keywords such as –Georgia.
While it might seem counter-intuitive to do something that drives people away from your web site, it can be useful, especially when you’re more concerned with the quality and characteristics of visitors than the volume of them.
To read more on negative keywords, visit http://adwords.google.com/support/aw/bin/answer.py?hl=en&answer=63235