Online play is measured by a statistic called BB/100, or Big Bets per 100 hands. The two major tracking software, Poker Tracker and Hold'em Manager measure Big Bets as twice the big blind. So if your BB/100 is 5, you essentially make 5 x 2 x Big Blind every one hundred hands you play, e.g. if you're playing at $1/$2 stakes and your BB/100 is 5, you would be making $20 every one hundred hands.
In live games, you would probably see 100 hands in two to three hours of play. Making $20 in that time is ridiculous. You might as well be serving tables and you'd likely make 3 times as much. In online play though, you could probably see 100 hands in an hour of play on a single table if you play 6 max. With a BB/100 of 5, that would equate to an income of $20 an hour. Now, for every additional table that you play simultaneously AND maintain your BB/100, you increase your income generated per hour. E.g. playing 5 tables simultaneously with a BB/100 of 5, at a rate of 100 hands per $1/$2 table per hour, you have an income of $100 per hour. This is why playing multi-tables gives an online player a significant advantage in terms of possible income.
I'm sure a lot of you have heard of players playing 20-50 tables at once, and you wonder how is that possible. I thought that too when I first started, but once I experimented with playing multi-tables, it was actually a lot easier than it sounds. Picking the right software is very important. I have used Full Tilt, Party Poker and PokerStars in my experiments, and right now, the best option seems to be PokerStars for a few reasons. First off, PokerStars has the most number of players at any one time, which makes it easy to start off 20-30 tables in a matter of minutes. PokerStars also puts in a lot of support for multi-tabling in their software. Simple stuff like automatic table pop-up when action is on you, table positioning memory, auto seating preference etc. make multi-tabling a lot easier. Another thing in their favor is the rake-back programme incorporated in their software which gives pretty much the best rake-back deals, especially if you manage to reach Supernova or Supernova Elite (I'm not saying all this because I'm getting paid to do so, which I'm not. This is just my personal perspective based on personal experience, so take it all with a pinch of salt).
Another aspect of multi-tabling is tracking. As you reach the higher stakes, tracking software becomes essential in aggregating your win rate (BB/100), hands per hour, income over time etc. Some players also used the Heads Up Display (HUD) to show opponent's playing statistics with VPIP (Voluntary Put In Pot), PFR (Pre Flop Raise), CBP (Continuation Bet Percentage), FCBP (Fold to Continuation Bet Percentage) being some of the stats likely to be used. These stats makes for easier decision making when you're multi-tabling and don't have time to observe your opponent's play.
Table and seating arrangement is very important as well. The less clutter there is, the easier and quicker it is for you to focus on what matters. With PokerStars, you can easily set the preferred seat location (I usually used the seat directly south) so your hole cards always appear at the same spot, making it easy for you to see and act. As for table arrangement, I used to tile the table across my monitor. The advantage of this is that you will be able to see all your tables at once, and pre-click a lot of hands you would like to fold, which saves time. However, since you're viewing multiple tables at once, the tables are much smaller, and if you play many tables, it becomes hard to focus. The best way imho (the method I'm using right now) would be to set your tables to automatically pop-up when action is on to you, and stack all your tables in the same location, one on top of another. This would mean that you never know what is going on once you've made a decision as the next table waiting on the list would pop-up after you've clicked (raise/check/fold) and you would not know the outcome till much later. This is not a bad thing though, as it forces you to make the best decision in that particular situation, based on pot odds, probabilities and stack sizes.
Hope this gives an insight on how multi-tabling is done online. I'm currently playing about 15-20 tables of SnGs at a time, with a win rate of about 20%-30%. I will write more about how I make my decisions when playing mutil-tables, and how various circumstances affect my multi-table play in future articles. Till then, try your hand at multi-tabling. You may find it a lot easier than you think. Good luck!
