Earlier quoted context omitted.
It's pseudonymous, because if they make a transfer later we'll still know it's the same people.
Can't you just generate a new address for every transaction you conduct and remain anonymous?
Unless you have some anonymous way of depositing BTCs into random addresses, all transfers into and out of that address will be stored into the BTC Blockchain _for life_.
No, seriously. Forever, for the rest of Bitcoin's history, there will be a record that two addresses transferred BTC between each other.
This will be timestamped, cryptographically signed, and archived by the BTC Network. That is... what Bitcoin is after all. It is the ultimate ledger.