I haven't used that service in a long time, so it may have changed, but the way blockchain.info used to "anonymize" bitcoins was way too vulnerable to traffic analysis. First, they charged a flat fee of 1.5% (which I believe was reduced to 0.5%), and when you sent the coins to your anonymous address, the fee would be subtracted, and the rest would be deposited to your real bitcoin address in exactly two transactions, within about 10 minutes. So if someone identifies your SR address as belonging to SR and they see the deposit came from another address, which they suspect belongs to blockchain.info, because the coins in that address came from two transactions a few minutes apart, then they merely have to look in the block chain for a transaction that occurred about 10 minutes earlier and involved exactly 1.5% (or 0.5%) more BTC. Now they are on the other side of the mixer and they can follow the transaction chain back to the exchange and your identity. There are much better mixing services that give you more options for how you deposit and withdraw your coins, along with charging variable rate fees, to defend against that kind of traffic analysis.