Everybody loves a joiner. Joiners are the companies that offer financial backing, customer support, and indemnification for open-source projects. They contribute code. They donate resources. They participate in developer forums and help to foster community.

Red Hat is a classic example of a joiner. But then, so is EnterpriseDB. Although its flagship product is proprietary, EnterpriseDB regularly contributes code to the PostgreSQL project upon which it is based. It even offers subscription support for plain-vanilla PostgreSQL. What's more, according to Astor, EnterpriseDB employs more members of the PostgreSQL community than any other company.

So who are the user companies, then? Try looking in the mirror. Most customers who deploy open-source software will never hire any developers to work on it. Most will never even contribute a single line of code, and their presence in support forums will consist of more questions than answers. That's hardly the ideal model of community participation. But that's OK, too, because users often have something else: money.

"A user can gain the benefit of a joiner in exchange for a monetary transaction," says Astor. When a customer enters into a commercial contract with a vendor of open-source software, that vendor in effect becomes the customer's surrogate, representing the customer's needs and wishes and taking on the burden of direct participation in the open-source community.

So the next time you're wondering if a particular vendor is truly an open-source company, Astor suggests you ask instead how that vendor represents its customers. Does the vendor understand the code base, contribute to the project, fund development, offer support, and participate in the community? Is it a joiner? If the answer is yes, then relax. The vendor is representing you, the customer, as a true participant in open source. The licensing terms it offers you on the back end needn't be anybody's business but your own.