Use Negative Keywords in Google AdWords to Avoid Costly Mistakes
If you're using AdWords to drive customers to your eBay sales, here's a good tip:
Google AdWords allows you to identify 'negative keywords' and filter them out of your search/ad placement. This allows you to screen out words that are commonly associated with your keywords but have no relevance. AdWords even does the research for you. You simply pick the ones you want to exclude from the bigger list they compile. The online marketer writes more about the pitfals of online advertising mistakes here.