If you have me, you want to share me. If you share me, you haven't got me. What am I?
The answer to the riddle is a secret. When someone has a secret, they may feel compelled to share it with others, but once they do, it is no longer a secret and they no longer have it.
That is correct. Do you have a riddle for me?
I have keys but no locks
I have space but no room
You can enter but can't go outside
What am I?