You have to be joking?!? Paste the private key of your BTC stash into some internet site web form? This is insanity if you ask me.
Well, if you have a better answer to his question, please share. Otherwise you are just a whining nay sayer.
He had a legitimate concern that was addressed by subsequent posters. The part that was missing, and that should be bolded, is that you create a new wallet and move your coins over before sharing your private key(s). This way you do not risk any BTC.