Both Joel on Software and Coding Horror readers formed the initial audience.
While Jeff wrote code for StackOverflow, and Joel did not, Joel provided and acquired the initial funding to pay for Jeff's work, and hired the other talent required to allow the site to launch. It was neither entirely Jeff nor entirely Joel's creation, and I doubt it would've been able to launch without both putting quite a bit of backbone into it.
Both Joel on Software and Coding Horror readers formed the initial audience.
While Jeff wrote code for StackOverflow, and Joel did not, Joel provided and acquired the initial funding to pay for Jeff's work, and hired the other talent required to allow the site to launch. It was neither entirely Jeff nor entirely Joel's creation, and I doubt it would've been able to launch without both putting quite a bit of backbone into it.