yes but me and some others can't signs, we do not have this option for exemple with coinpayments (and some others too don't allow to sign, i'm using another for my bitcoin wallet and they don't allow to sign too).

the reply from coinpayments support :
"There is no way to sign messages with your deposit addresses. Remember never to do anything that would require you to sign from our addresses or otherwise prove ownership of them."

And the worst i tried to deposit to links account to coinpot, all depositing was credited on my coinpot account but it didn't link any moonfaucets and supports don't replys :x << and this is the problem >>
(plus : on my coinpot account the wallets address i use for withdraw are the same than my moonfaucets account for login since coinpot open...)