When I post to other stack exchange forums, the post shows my user name. In Unix & Linux, it shows my user number. What am I doing wrong?
See my comment to the top answer in How to log whatever I enter in terminal to file
It actually is showing your display name -- here your display name is "user23861". You can edit your profile to change it -- the link is at the top-right of your profile page:
You can also go to the "accounts" tab on your profile on another site (e.g., Super User), and click the "Copy profile to all Stack Exchange accounts" button at the bottom:
When it copies your SU profile here it will also change your display name