The good news is that cracking your knuckles won't cause arthritis or cartilage damage as many people suggest.
But it can have some detrimental effects that you should know about...
The danger of cracking your knuckles
When you crack your knuckles, what is actually going on it that a space is forming within the "joint capsule" where your bones meet.
This capsule is usually filled with a liquid called synovial fluid that keeps joints lubricated and moving smoothly, but when this extra space emerges - gasses normally dissolved in the fluid escape and fill up this new-found space.
This is what causes the popping sound.
While there is no danger of arthritis from this process, you can weaken your grip strength and cause impaired hand function after some time.