PayPal is excluded, if you didn't understand it, the first time.
I just want a place, where addresses are temporary. I don't need to have one alone.
That's all.
Sorry for that. Looks like some people weren't reading the thread.
When you receive Bitcoin to your address, sending will effectively be from that address.
So if I receive 0.01 Bitcoin from three different people and then I send 0.03 Bitcoin to someone else, it will be sent from the three different addresses that I received from,
at the same time. Therefore, the closest that a person could really get to finding what that transaction was is that any of the people who sent you 0.01 Bitcoin can see that you sent 0.03 Bitcoin (they can't see what it was for or any information about it though).
If you are sending less than your total balance, then the Blockchain wallet will automatically send with as few inputs (transactions you received/addresses) as possible which makes the size of your transaction smaller thus reducing fees. With "real" wallets which aren't online, like Electrum for example, you can choose what addresses to send from.