The overnight IT guy was caught watching porn while working (this was over a decade ago, he was in the office every night and not a remote worker). How was he caught? He was saving the pornographic photos on a shared network drive...
When confronted, he didn't try to deny anything, his explanation was simply, "That's just my thing."
The subreddits for individual sports teams, posting comments in game threads with a hundred other fans of your team from around the world.