The short answer:
Online poker players have nothing to worry about. The only time you would get in trouble with internet poker in the USA would be if you actually owned a poker site where players can play for real money.
The long answer
Online poker resides in a legal grey area in the United States. There are no federal laws that specifically outlaw the activity. However, some politicians have tried to apply the wire act to online poker. There has been much debate over online poker in recent years but so far, the right to play poker on the internet has withstood the test Bandar Domino.
Online poker has been a possibility for US citizens since the late 1990s. Some players have played for years and years online and there is yet to be a case of a player being charged with playing poker on the internet. The law is simply too vague to make it a good case for any player to be charged with a crime.
Where you would get in trouble with online poker is if you actually started an online poker site where players could play online for real money. In that case, you would get in all kinds of trouble. The states like their monopolies on gaming so you can rest assured they will prosecute you if you try to start a poker site or hold an underground poker game.
Although some states (most notably Washington State) have laws on the books against internet poker, no player has yet been charged with a crime for playing poker online. Existing laws are simply too vague and poker is too popular for there to be a realistic chance of anyone actually getting in trouble for playing poker on the computer. Additionally, public opinion is overwhelmingly in favor of online poker so even the most overzealous DA would think twice before taking action against an online poker player.
The UIGEA, or Unlawful Internet Gambling Enforcement Act, was signed into law in 2006. This act does not make online poker or online gambling illegal. This act instead targets banks and financial institutions, demanding that they identify poker and gambling transactions and block them.
To date, banks have had extreme difficulty enforcing this act. Billions of transactions take place every day in the US and banks don’t have the resources to identify individual transactions. In late 2009, the implementation of the UIGEA was delayed for 6 months to allow for more debate and to give banks more time to comply with the law.
So far, the UIGEA have proven to be an impotent piece of legislation. The only effect the UIGEA has had is that sometimes credit card transactions to poker sites are blocked. In those cases, players simply choose a different deposit method and continue on as normal.