Well, many people treat internet chess differently. My uscf rating is much higher than my chess.com rating. That is because I treat OTB chess more seriously. I sometimes get a craving to play chess when I'm drunk, so I log on and damage my rating.
Chesscom Vs USCF/FIDE Rating

I find that for the most part, people's offline ratings are higher...up until you get to around 1800-2000. At this point, it is rather hard to win games unless you are contentrating as hard as offline (which if you have a lot of games going, this can be quite impossible.)
Though strong bullet/blitz players offline are strong online, as long as they have a good mouse to back it up.

For reference
Offline:
USCF Regular: 1911 (generally perfomances around 1850-1950, I am going down though)
USCF Quick: 1761: Same, just harder opponents
USCF Blitz: 2063: Generally play against titled players monthly, consistant
Online
ChessCom Correspondance: 1676, though it's around 1770-1800, blame recent timeouts.
Live chess: Standard: 1696
Live chess - Bullet: 1659 (though it's generally around 1700/1750, espec in 2+1)
Live Chess - Blitz 1976

I have no idea why this showed up on my wall, but I agree that my USCF would likely be higher than my chess.com rating. I just don't focus near as much here. The pressure of tournaments can unhinge a person too, but I think overall it would work that way. I think I am 1560 something on uscf but would likely be quite a bit higher given more games... and that is only after 5 or 6 games.
A friend and I was talking about how his chess.com rating differed from his USCF rating. A few years before he started playing on chess.com he very active in USCF. He played about 50 games in USCF and has completed 250 on chess.com. He stopped his USCF endeavors around the time he started on chess.com His rating is a 1350 in USCF and 1650 on chess.com.
He is convinced it is harder to get a higher rating on USCF than on chess.com. I disagree. I told him that he has gotten much better since he stopped playing in USCF for one. Secondly, on chess.com you as well as your opponets may have serval days to think threw a single move. This can help avoid concentration issues like coming back to a game when you are more focused. Not only that he uses the analyze function as well as anyone else can to help enhance their depth unlike you would be able to playing in person over the board. So i personally believe chess.com competetion is tougher to beat than USCF with equal rating. His only argument for playing in USCF was playing in person in tournament format can have immense pressure on someone. I won't disagree completely with that but I will say that some people enjoy such pressure and play better in that environment.
Everyone knows that several GM’s that play on chess.com that are involved in FIDE as well. I have noticed that most of their daily chess rating is much lower than their FIDE rating.
Everyone please share your thoughts!