Good search marketing is about excluding people who are unlikely to buy from your company, so it helps to maintain a blacklist of keywords that are unlikely to generate useful leads. Keeping an up-to-date list can be hard work, but it's the best way to get more bang for your buck. For instance, if you sell industrial dryers or mixers, there are going negative keywords galore that you'll need to employ to avoid the consumer market, those looking for a new Maytag or Cuisinart from clicking on your ads...
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