Can someone tell me what's with the yellow rubber ducks? What is the story behind it ( or its usage which , i guess, is related to debugging)?

It's often useful, when stuck on a bug, to explain what the code is doing to someone who has no idea about the system. In the process of doing so, you'll often realise exactly what's going wrong. Then people realised that a rubber duck also has no knowledge of your system, so you can explain your problems to that instead.

Stay tuned- I believe Andy Hunt, who made rubber duck debugging famous, will be the first featured guest on devRant's new podcast series. Should be a lot of fun.

@Max-Appeal there are developers with non-dev friends?

... there are developers with friends?