Using Negative Keywords
Negative keywords are powerful tools in search advertising campaigns that are often under-utilized or overlooked. Whether using Overture, AdWords, or other search advertising programs, negative keywords can significantly reduce advertising costs and allow you to focus your ad dollars on the most effective keywords.
When NOT to Show Your Ad
Negative keywords permit advertisers to specify when ads should not be shown, such as when a keyword has multiple meanings or is part of other popular queries.
Let's consider an example of a specialty cookie company that advertises on the keyword "cookies". People would see the ad if they searched on "chocolate chip cookies" or "specialty cookies". Paying for these clicks makes sense. However, the ad may also show up for people who search on "web cookies" or "eliminate cookies from my hard drive".
Most ads sufficiently specify the product to which an advertiser refers, hence we would expect few erroneous clicks. However, many users click on ads without reading the text and realizing that they refer to something other than what they are looking for. Believe it or not, this is a substantial problem, particularly for highly placed ads (the problem diminishes further down the page). Even a few erroneous clicks can generate significant expenses on competitive keywords.
Even if we ignore the effect of spurious clicks, the extra ad impressions are problematic for two more reasons. First, programs like AdWords determine ad placement partly from click-through-rate (CTR), thus showing your ad when it is unlikely to get clicks will result in lower CTR and lower placement. Second, extra impressions skew statistics that would otherwise provide valuable insight into user behavior.
Finding Negative Keywords
Negative keywords are remarkably easy to find. Simply type the phrase of interest into a search engine and see what comes up. Searches on common and short phrases almost invariably turn up results that don't conform to your intended usage. Look at what other words always appear with your keyword. For instance, a search on "cookies" turns up many pages that include the words "Internet" and "web". By adding these as negative keywords for our ads we can prevent the ad from showing when the words "Internet" or "web" are included with "cookies" in a search query.
The easiest way to find negative keywords is with Overture Keyword Selector Tool. A query on "cookies" provides a list of the most popular searches that included that word along with how popular each search was over the last 30 days. Here are some negative keywords turned up by this technique (your results may differ):
Not only is this a very quick way to find negative keywords, it's also based upon real user behavior. You can try inferring search phrases from search results, but nothing beats real search statistics
In summary, negative keywords help target keyword ads to likely customers and can grealty improve campaign cost effectiveness.