I have a couple things to say about online poker... it is more addicting than cigarettes, alcohol, weed, coke, and extacy. In my personal experience anyway....
I played pretty much everyday for like 4 years, first under a fake account my 18 year old friend transferred me money into, and the finally once I turned 18, under my own accounts with my own credit card! 18 Is the magic number here in Alberta, and boy did I drink and gamble. I Had some really good winning days ($3000+) and had some pretty bad losing days ($500+)... In the end had over 1,000,000 hands under my belt (1,000,000 averages out to 40 hours a week, 10 tables at a time, for 4 years)
I played mostly tournaments, probably upwards of 100 a week... the total buy ins would easily totally over $200,000... and probably be closer to $500,000.... it was fun... I also dabbled in cash games playing stakes with a big blind as big as your average home game buy in, but found my niche in tournament play. The four years turned into about $40,000 profit, which is pretty terrible considering that is less than a 10% ROI... and only about $10,000 a year... I decided once I turned 21 I was going to head down to the WSOP and take my shot, so I took that 40,000 to Vegas... entered as many WSOP events as I could afford... I ended up busting out of every single tournament but one, it was one of the $2000 NL Holdem Events... I placed 3rd... for over $200,000. It was one of the greatest moments of my life.
I felt lucky and deserving of a hot streak, one you hear about through online forums, guy turns $200,000 into $20,000,000 in two weeks...I had turned the past four years of $10,000 a year into $50,000 a year... so I went to my hotel lobby and asked to extend my booking two weeks, I was going to celebrate! I was young dumb and 21... so I took $50,000 of that $200,000 and sat down at $250/$500 NL HE table. I had a look around me, and noticed a few pros I had seen online sitting down. I made a mental note to avoid playing any big hands against them without being confident it would be profitable.
Long story, turned really short... over the next week I lost $200,000... got really really high and blackout drunk, woke up in a hospital with a $26,000 medical bill, and a $10,000 credit card bill.
Just keep it under control, and unless you have 40 hours a week free time to dedicate to it, and read tons of books, and forums and such, then don't plan to make any money off of it. It's a fun hobby.
I recently self banned myself from Full Tilt, Pokerstars, Party Poker, Titan Poker, Paradise Poker... and the other sites sucked to bad to ever bother with.
That is my intervention.
Good luck.