It's a word or phrase that you add to your Campaign or Ad Group in order to prevent your advert being displayed in response to a search that may not be relevant to you. Let's look at a quick example:
You run a web site that sells digital cameras but not digital camera batteries. So the last thing you want is for the battery searcher to click on your advert.
Now you could just bid on the exact phrase 'digital cameras' and the like to reduce the risk but if you want to get the balance right between maximum exposure but avoid irrelevant clicks, then I suggest you use a combination of phrase match with plenty of negative keywords thrown in to the mix.
In the example above, you could bid on "digital cameras" but add 'batteries' as a negative so preventing your ad being displayed for a search containing this word.
Why Bother?
Quite simply, you'll save money and improve conversions for your AdWords campaign.
Google rewards relevancy meaning that in very simple terms, the higher you can get your Click through Rate (CTR) the more relevant your advert is deemed to be. As a consequence, it is perfectly feasible for an advertiser at position #1 to be paying less than advertisers in lower positions who haven't worked as hard at optimising their campaigns. Clearly, if our 'battery searcher' doesn't click on your ad (and why would they?) then your CTR will suffer.
Conversely, they do click on your ad. This is what I call a 'curiosity click'. OK, your CTR hasn't suffered but your budget certainly has. A wasted click combined with quality scoring, means your campaign has just taken a real knock.
How Do You Find Negative Keywords?
There's many ways to skin this particular cat but like so much with Search Marketing, it starts with good keyword research.
Research your keywords then copy these to a new text file or spreadsheet. I then search and replace (with blanks) my primary phrases and words that are relevant. This then leaves words and phrases that are irrelevant to our campaign, i.e., our negative keywords.
This process can take a while to work through and refine. It's important to be sure that what you're left with is a list of words/phrases that you definitely wouldn't want your advert to be displayed for.
The time you spend identifying your negative keywords will be well worth the investment and will pay you back many times over. You will start to see your CTR climb, costs reduce and conversions increase. That is what you want from your AdWords campaign isn't it?
