Strength discrepancy

Saw quite a few 2000+ at online chess yet with horrible ratings/play at live chess.

What might be the reason?

I find this a lot too, I think it's because in a lot of cases the top correspondence  (turn-based) players rely extremely heavily on databases, opening books, and the ability to analyze the board (move the pieces around).  Once you take these tools away from them they are like fish out of water.   Either these tools have become a crutch of sorts and they can't play well without them or they simply do not wish to improve their OTB chess skills.  I noticed this a lot at Gameknot as well when I used to play there. 

I agree though the discrepancy is odd because with all the skill and deep understanding of chess some of these high rated players display in their turn-based games, you'd think they'd be able to carry at least a good portion of it over to Live chess.

Hummm...I always think the same thing Sconsc. 

How can someone be rated 2000 or 2100 and then be a 900 to 1200 in quick?  I understand that some people aren't fast, but if you are that strong in turn-based then it is quite suspicious indeed.

Currently in quick I hover around 1600, but I can still give the best quick players a good game and usually lose to them on time.  I actually drew a 2200 quick player and had a winning position, but my heart was beating to fast at the prospect of winning and I blundered a rook. 

The point is that I'm around 2000 turned based and can prove it in my live games where my rating is about 200 points lower in each category (long, blitz, quick). 

The (question mark) in your post has a lot of well placed innuendo.

There can be many reasons. Look at Judit Polgar's horrible result in the recent world blitz championship.

In most cases I would say it's time. When you get comfortable playing with certain time controls and you have adapted your play to them then you suddenly start playing a different time control (for example blitz) you'll play poorly until you adapt and become comfortable with those new time controls.

Another aspect of time is that you get more time to think when you have 24h+ to consider your move, alternate moves, and your plan.

With "live" chess you also have distractions in that moment that can effect your play which would not do so in "online" chess because you can simply delay making your move in that moment.

The question is kind of like asking  "why did Judit Polgar perform so horribly in blitz?" at the end of the day she's still a GM and that won't change despite a poor performance in 16 blitz games at the world blitz championship.

If you were to judge Judit's performance in those 16 games you would say there's a discrepancy there as well. So I'd ask you "what might be the reasons?"

;)

It is a lot easier to make good moves with three days per move to decide than it is with five minutes per game, as Oracle said. 

oh wow, you want to see some bad blitz chess? You should check out this Chessroshi guy I saw. I mean, seriously, you'd think a spidermonkey took the game over. This guy had absolutely no respect for authority either, tossing queens away like some sort of christmas sale. I heard he only plays standard time controls, they ran out of paper bags in his hometown to hide his face in shame.

 one could cheat in a 10min. game, evin in a two min. game.

    Set the time at two minutes and your program at one.

just think about how much our ratings would be going up if we stopped wasting our precious spare time pondering other peoples ratings and it's relationship to other peoples other ratings.