Many of those other so called search engines are nothing more then FAA Links. These are the same bogus search engines that you will be submitted to on a mass submission. Remember many search engines are now rejecting mass submissions. We hear this all the time.
People say their site is already listed on the search engines.
But when we enter there product or service they do not show up. Sure they may be listed but they will only show up if you enter their full business name. You would probably be surprised, but many people in your own town don't even know who you are. Remember you are trying to reach a world wide audience on the internet, they definitely do not know your name. Now if you were in the categories that pertain to your product or service the whole world could now find you.