Basically, the tax agency views bitcoins and other cryptocurrencies as property and not currency for tax purposes. And although you may not receive a Form 1099 from whatever exchange you trade on, you remain responsible for paying taxes on gains.
U work for me, I will give U a motorcycle, its still income in view of IRS, of the FMV of what you got, all the games have come & gone, including getting paid in ten cent silver coins, really worth $10 each.
IRS is NOT stupid,
Houses, Dildos, beany-babys, or BITCOIN's all have a fair market value, to be taxed, unless its an estate gift, ...but then that should have been already declared,
The entire deal, is that they just 'take it all', say you sold $50k on coinbase, and that was 3+ years ago, you get a letter you owe $150k in back taxes, penalty's and fines, then they just take out all the money from your bank accounts and put a lien on your property, the burden is on U, to file retroactive tax forms and PROVE that taxable income is less than they report, but then you still have to pay all the fines and penalty's, and don't forget the fortune that your CPA & Lawyers charge you for having to defend you against the IRS, and good luck getting your money back from the IRS that they nabbed from your bank accounts, 401k's, credit-unions, and trust-accounts.
Moral of STORY, if U play BITCOIN, then don't use a USA backed exit when you get off the BITCOIN-HIGHWAY.For all you PUMPERS trying to get NORMAL-JOE on the BITCOIN train, remember that your really making his life to be a HELL ON EARTH
BITCOIN was never to have mining pools, gov controlled exchanges, or any of this current BULLSHIT
BITCOIN was a peer2peer barter transaction environ, off the grid, and unseen by GOV.