What is a “locked” post?
I came across Jon Skeet Facts question, which is off the track, but I found it interesting.
Just want to know, why can't I upvote or comment on any of the answers. Is this any feature of SO?
No more activity is allowed on that post because it is locked.
It was never a good, on-topic question for Stack Overflow, so it was migrated here to Meta to preserve it long ago. It was subsequently locked because it still isn't a very good Meta question either. It's just funny and that's about all it has going for it.