As a financial planner and investment adviser, Betty Hedrick knows the value of numbers. By cross-promoting the Hedrick Co., her $600,000 business, with six other small business-to-business service providers, Hedrick gains a community of helpful colleagues and access to new prospects. The cooperative arrangement also enhances her company's image and boosts sales.

The seven companies jointly produce a quarterly newsletter and mail it to all their clients. While none of them could do it alone, working together keeps the burden manageable and the costs affordable. Plus, the shared newsletter "expands the types of expertise available to our clients," says Hedrick, who is based in Mercer Island, Wash. Every company involved gets introduced to the others' clients, expanding everyone's base of potential customers ? while offering a wider range of services to the customers they already have.