There is no doubt that it is a very difficult task to figure out which are the effective SEO companies and which are the that are not going to do a very good job for you. Business owners are generally faced with making this decision themselves even though they literally have no idea at all what makes one company good and another company not so good. If you compare all seo companies against each other, they all look pretty much the same and tell you the same things. So what is the best method of figuring out who is good? This is going to be based upon their portfolio, and the quality of success that they have had for other clients. If they have done a good job with clients that are sort of like your business, then you can assume that they will probably do a pretty good job for you as well.