If you are using site-targeted campaigns with AdWords it’s very easy to root out invalid traffic depending on your goals. If for example you need many pageviews, have a look at your AdWords analysis in Google Analytics or any other analytics software you are using and check how many pageviews an advertiser is bringing on average. If your target is 3 PVs per user and a site is only generating 1.2 PVs then you know that the traffic you get is not really qualified.
An even easier method is to use time spend on the site. When you see zero time spend on the site it is highly likely that humans are not involved. This is commonly known as click fraud, but before you start banging on Google‘s door, simply remove the sites from your AdWords campaign. If your goals are e-commerce driven then it is even easier to track conversion. Just make sure that you are using a good timeframe. If a site has not generated conversions over 3 months and the traffic quality looks poor in terms of average time spend on site and pageviews, then it is easy to make an informed decision as if you are going to continue the campaign with that particular traffic source.
In a way, by doing this, you help the industry as a whole. The less money spammers make, the less attractive it becomes for them to get involved. It will also work wonders for your budget.
