[jleader]

Any company selling to a group of people has to understand the needs of their customers.

Many companies do this by hiring people called "marketers", who specialize in studying the needs of other groups of people.

An alternative is to create products for a group you belong to.

Hence, if a web developer (who is not also a marketer) is going to develop a product by themselves, it might make sense for them to create a product for other web developers.

Note that this doesn't mean all web developers will only make products for other web developers. Many web developers work for companies that have marketers to handle the "understand the needs of your customers" part. Other web developers have (or can teach themselves) sufficient marketing skills to develop products for people unlike themselves. Still others develop products for other groups they are members of (e.g. web developers creating products for people who share one of their hobbies).

I don't know why the original article didn't include these last 2 categories of developers, though.