Who you keep out can be as important as those you let in....sometimes, more so. I don’t know about you, but I don’t want some bum to waltz into my house, make themselves comfortable in my recliner, eat my food, get on my computer, and use my hot water. And, I’m sure as heck not doing to PAY for their gas to get there.
So, why should website traffic be any different? When you are using keywords to attract potential buyers to your website and you are paying for the cost of them to visit, you don’t want or need any “looky-loos” breezing through your site on your dime. This is where “negative” keywords come in handy. They keep people who are not really looking for what you are offering on your site from seeing it and visiting, thus saving you money.
It’s kind of like moving and changing your phone number and not telling your freeloading second cousin. He might be looking for you, but he can’t find you…