The IRS is attempting to identify Coinbase users by leveraging a John Doe Summons. A “John Doe” summons is a special form of summons to look for tax evaders that allows the IRS to obtain information about all taxpayers in a group or class of people, even if the agency doesn’t know their identities. This news should make everyone dealing in crypto-currencies cautious. Since learning about this, I think its more likely the IRS also attempts to obtain additional information about users of Bitfinex and other exchanges that are connected to the US dollar. I think its also likely that as certain crypto currency wallets and exchanges become more liquid, it will make them a target for the IRS.
http://blogs.wsj.com/law/2016/11/21/bitcoin-exchange-extremely-concerned-with-irs-effort-to-identify-users/
http://www.reuters.com/article/bitcoin-irs-coinbase-idUSL1N1DL0MW
