This common question is asked almost every day at poker forums around the internet. The short answer is no, online poker is not rigged. It has been discussed time and time again but no matter how much proof is offered showing that online poker is not rigged, people still claim it is.
If you play at a small, unheard of poker site, sure, anything is possible. But at the major poker sites where most poker players play, it's been proven countless times that everything is on the up-and-up.
One of the most common complaints I see about online poker is where people will say things like "its crazy! These donkeys play crap and always hit some kind of lucky garbage on the river! It never happens to me offline!"
If you have any kind of background involving statistics or, hell, anything that requires hypotheses and proof, that is one of the most annoying kinds of complaints in the world. Random first hand accounts don't mean anything statistically.
First of all, people remember their bad beats much more vividly than they remember all the times their pocket kings won the pot just like they should have. Second of all, you play a lot more hands in online poker than you do in live poker, so you're going to see more statistically unlikely events. It's a numbers game.
Against any random hand, AA will in about 85% of the time. That's great but 85% is hardly a certainty. If you play enough hands every day, your AA is going to get cracked on a daily basis! It's completely normal and expected for favored hands to lose - it's statistically impossible to expect your strong hands to win every time.
Every major poker site is tested for pure randomness and fairness by independent auditing organizations. PokerStars is tested by two separate organizations: Cigital and BMM International. These two organizations are industry leaders in independent audits and have audited the likes of AOL Time Warner, Motorola, General Electrics, Visa and many more.
Other major poker sites are tested for fairness by Technical Systems Testing, another big name independent auditor of casino software. You can even visit the web pages of these companies and view the results of their audits for yourself. Any site could put a "tested by TST" sticker on their website, but when you get the information from the auditor's website, you know it's legit.
On top of that, thousands of poker players use poker statistics tracking software to track their play and study every hand they've ever played. These players have databases containing millions of hand histories. If something wasn't adding up, it would stand out like a sore thumb.
And last, let's use a little logic here. The owners of the major online poker sites are raking in billions of dollars. The guy who started Party Poker is a multi-billionaire now. Do you think the owners would put such massively lucrative businesses at risk just to screw your AA over once in a while? It just wouldn't make any sense.
Online poker is most definitely not rigged and I've used it to makes lots of money myself. All it takes is a willingness to learn the right strategy and the ability to shrug off the occasional bad beat. If you can do that, you too can become a long term winner at online poker.