Advise
I have played alot both online and land based. I have won alot and lost alot! Most of my losses are from staying too long! My advise - know basic strategy well and win alittle each day. Don't be greedy. Settle for a 10 to 30% return each time you play. If you strictly just want to play for fun just bet very small amounts. Partypoker.com has blackjack with a minimum of a nickel! I have noticed it seems that online strange things happen - many double downs result in a very small hit card and it is not always wise to hit on 16s when playing online. In other words be cautious and mix it up a little when playing online. It also seems sometimes online you will have runs of consistent loosing hands and runs of really good winning hands rather than just a back and forth game.
Good Luck!