This directly contradicts their statement on the website:
Therefore our servers only hold encrypted private keys and neither we nor anyone else can spend your Bitcoins. Only you.
Do not use strongcoin thinking it is a hybrid wallet. It is not about if you steal any coins or not, but this shows StrongCoin do have access to your coins. Imagine if they were hacked, or if the owner did a Instawallet. Use Blockchain.info (the chrome extension) and back up your private keys.
Info: https://bitcointalksearch.org/topic/is-strongcoins-hybrid-wallet-a-lie-or-rather-are-all-hybrid-wallet-a-lie-186051
This is pretty huge.