How does the blockchain.info shared receive work?
The Shared Recieve is also a mixer. When you get a new shared address, it will also show the "Forward To" address which will be one of your main addresses. If anyone sends bitcoins to that shared address, Blockchain.info will send them through its mixer then send it to the "Forward To" address. However, there are transactions costs and blockchain.info's 1.5% fee. It's meant for bigger amounts.