There are a lot of agencies out there that promise to help you with your search engine optimization. Some of them are great services that can boost your visibility and drive traffic to your site. Others are a bit unscrupulous and try to boost your site’s ranking through nefarious means. And still others outright lie about what they can do for you and what you need, tricking you into paying for their services by promising results that they can’t really provide. So how do you tell the difference? Here are some things to look for.