I know this was mentioned before a while ago, but I just found out about this feature that tells you how anonymous your transactions are.
https://blockchain.info/taint/TYPE_ANY_BITCOIN_ADDRESS_HERE Obviously use any address you want to lookup in the URL.
"Taint is the % of funds received by an address that can be traced back to another address.
This pages shows the addresses which have sent bitcoins to [BITCOIN_ADDRESS_ENTERED]. The data can be used to evaluate the anonymity provided by a mixing service. For example Send Coins from Address A to a Mixing service then withdraw to address B. If you can find Address A on the taint list of Address B then the mixing service has not sufficiently severed the link between your addresses. The more "taint" the stronger the link that remains."
Edit: I think this also works with the onion URL but you can also do this by searching any btc address on blockchain.info/onion url then clicking Taint Analysis on the top left of the page where it says "Tools".
Thanks man, it's only been out for over four years.
Nifty isn't it?