Adding negative Keywords can really help your performance in AdWords. Doing a search for `university places` on google.co.uk as expected throws up some ads for Uni places. However my eye was caught by the one advertiser, Google, who is promoting a different kind of `places` in this case an ad for Google Local Listing. Clearly someone has put a keyword(s) on Broad Match and has not been regularly checking the search terms that it actually triggers on. For occasional users of AdWords the idea and practice of using negatives can be difficult to grasp. This is a pretty good example where the use of a negative keyword ie `university`would dramatically lower the number of unwanted impressions resulting in a better CTR and probably lower CPC.  Mind you this is likely not a real cost for whoever placed this ad.

Google Places ad showing in the wrong place CLICK FOR LARGER IMAGE