Playing on-line Poker

I used to play Poker on-line but during one of the many power cuts I lost a lot of money. Then, shortly after one of the biggest poker sites, Full Tilt, had millions 'stolen' by the US government, they wanted the tax on peoples winnings I suspect, unfortunately they nicked everyones money not just US players and busted the company. Good job I was not playing. I just registered to play on a different site today, 888.com, and they have to have your NIE number, (all on-line gaming sites have to abide by this directive from the Spanish Government).and they have the means to check it. Who else then has access to your personal data?. Does this also mean I would have to declare my winnings for tax purposes? and do 888.com tell them how much you have won/lost?. Talk about big brother.