It sounds like they have a dedicated customer support team and the on-call programmers are the second-level support. Take a look at the examples DHH gives of th

It sounds like they have a dedicated customer support team and the on-call programmers are the second-level support. Take a look at the examples DHH gives of the work on-call programmers do- "We spend time trying to figure out why emails weren’t delivered (often because they get caught in the client’s spam filter or their inbox is over capacity), or why an import of contacts from Excel is broken (because some formatting isn’t right), or any of the myriad of other issues that arises from having variable input and output from an application that’s been used by millions of people."