Originally the Internet was developed to enable the sharing of information on a common platform with others in their related fields. 
A common protocol or computer language was developed, which allowed very different computers all over the world to be talk to each other. This sharing of information accelerated research and development in almost every area human endeavor.
In the business world the free exchange of information is not exactly the accepted formula for success. But on the net, things work a little differently. The number one reason people are here in the first place is to find information and solutions to problems. 
Just as the nature of a vacuum is to fill itself up, in business a need attracts a solution. Business success of at its core is simply to "find a need and fill it". 
Have you ever wondered that Burger King, and Taco Bell locate their stores next door to McDonalds. Everyone does more business precisely because people visit the general area when they want fast food. Since everyone on the block is selling fast food they choose the product that satisfies their hunger at that time. The same relationship works in shopping malls.
Shopping centers are successful in the real world because they attract more traffic than any single storefront might attract on its own. The Internet as a whole operates much like one big shopping center. 
Internet malls rarely offer an advantage for consumers who want as much choice as possible. Link rings, testimonials, and referrals serve the same purposes on-line. 
There is plenty of money to be earned on the Internet your willing to look at the long run. Internet marketing is niche marketing. Cooperation is one of the most powerful secrets to Internet success. Rather than attempting to be a specialist in every aspect of your special area of expertise share the limelight with others.
In business it's often better to be a key player on a minor league team than a bench warmer on a major league team. If your product is not the best it's more profitable to sell someone else's product than lose the sale or lose the trust of your customer. In the long run it's more profitable to grow a customer for life than to make a sale that isn't the best long-term solution for your customer.
Successful businesses depend on satisfied return customers. When someone gets a referral from a source they trust it's much easier to make the sale. I give testimonials whenever I find a product I can recommend. It turns out that I get at least as many referrals from others as I give out. Much of my income comes from referrals from so-called competitors, many just returning a favor.
Many successful Internet marketers are doing business in this manner on-line. Affiliate programs and viral marketing approaches along with other forms of "pay per action" selling are becoming the normal way to grow an on-line business. While this approach may not the fastest way to grow a business it's a great long-term strategy. 
Cooperation builds trust and creditability on-line; trust and credibility in turn builds sales. Rather than fear my competitors I embrace them. It simply makes good business sense to cooperate. Prime the pump; give if you want to get.