Giving Your Kidney To Your Mum, Slipping Your Friend A Twenty: People Reveal Their Biggest Anonymous Acts Of Kindness

Online discussion threads have become a place for us to bicker, vent and breed negativity.

But here's one with a difference.

A refreshing online forum on question and answer site Quora has hit the headlines, for all the right reasons.

"What is the nicest thing you've ever done that no one knows about?," the thread asked.

So far, the question has generated more than 200 responses from users all sharing their stories of their anonymous acts of kindness, some kept it anonymous, others have revealed their names.

Top stories include the man who gave his mum a kidney, but she doesn't know he did, the woman who slipped a twenty into a cash-strapped friend's wallet and the man who bought his parents a house... 

Generosity at its utmost... 

Making childhood fantasies come true...

Money can make a difference...

A big donation... 

A friend in need...