It used to be quite easy to find free poker sites from the US. They were basically everywhere! Then the Texas Holdem poker boom hit the US and also the rest of the world. A lot of people started out practicing on those free pokers sites, but got addicted. They got hooked to poker sites and moved on to higher and higher stakes poker. The government realized the risks of poker becoming so popular and the number of addicts rising that it changed gambling laws. Many online pokers sites where actually closed down.
Of course there are still some internet poker sites to be found on the net, but in former times you could find much more and much better sites. Most of the sites nowadays pay almost nothing and use mainly advertisements to finance their sites. Many players find that really annoying and have turned away from online poker.
There are a few sites that are still pretty good and used by a large amount of players. With a little internet research they can be found quite easily. Also there is a huge number of poker blogs and forums on the net. There you can inform yourself about different poker games, poker rules or poker cheats. Many of them give novice poker players quite a good insight into the game and are therefore recommendable. If you are a experienced player those sites won’t show you anything new. You should rather go for poker forums where you can discuss different poker topics with a variety of people.
In any case, just because the really good poker websites were closed, you shouldn’t stay away from poker as it is a really fun and interesting game!