Yellow pages started off with just one purpose, exposing business to customers. But now, it might render not so useful with all the different ways that you can advertise on the internet, still millions of potential customers search the yellow pages for businesses they need. There are various online yellow pages over the web, and it is a great way to advertise your business, it is efficient, direct and cost effective. It is proven that if a business is listed in the yellow pages, their sales increase by a few folds.
The reason this is a good marketing technique is because the whole system is made for sole business purpose, while other search engines index everything around the web, which does not always pin point the business a customer is searching for. The other benefit to it is that when search for a business category, your business information might show up on the first page, or at least within a few pages, while on google, you business website link might show up on page number 20, because of so many different hits on other websites.