Success is when you are doing what you enjoy and accomplishing your goals.

I should explain the differences, seeing as I'm the one who suggested these phrases.. ;) They mean the same thing, however the grammatical differences are subtle... "What does success mean to you?" = asking about the action ("to mean something"). "What is success to you?" = how do you understand "success"? What's your own opinion? This is the most "open" of the three questions. Asking about the thing ("success"). "What is the meaning of success to you?" = asking for your personal definition of "success".

What does success mean to you and what is the meaning of success to you are both correct. Or you can say, for you, what is success?

Success is the ability to use whatever resources you have to achieve a desired goal.

In my opinion, success just likes a moutain. When you at the foot of the moutain, you have to look up to its height by its spirit. You, however, one day, at the top of the moutain will feel everything is not that hard. But you know, the process can not be forcasted. Success is a star but it is your star, only shings for you.