Better the opposite - date by default and on hover human readable. People would more likely want to copy the actual date than the human readable delta.
> People would more likely want to copy the actual date than the human readable delta.
I agree that this is true when copying, but text is primarily for reading, not copying.
Anyway, in the context of a comment/activity thread, how long ago from today that an entry was tends to be less important than the age of the comment relative to the other comments.
How is this "better at a glance"?!