One user sees 3wk-old nameserver?!

[pdxuser]

How do I diagnose and fix this problem: Exactly one user reports that they are still seeing my old site through a nameserver I switched away from three weeks ago. What could be the cause? What do I tell them to do? What do I do?

[pdxuser]

Solved. My first response, of course, was to show them how to do a hard refresh. They just got back to me and told me it worked. Tada. Weird that this would be cached for so long, though.