http://walletdvl5avrmoxk2fwsf5b76zkmbkoo3r6kqeesq5hsgnq7xhbciad.onion/blockchain-attacks-on-privacy
Once the clusters are obtained the adversary can try to link them real-world identities of entities it wants to spy on. For example, it may find wallet cluster A belonging to Alice and another wallet cluster B belonging to Bob. If a bitcoin transaction is seen paying from cluster A to cluster B then the adversary knows that Alice has sent coins to Bob.