The simple truth on this matter:
1. Never forget this is entertainment and no wise person would ever try to make money from unverified info like a posting board.
2. Sharps aren't quite as sharp as people think. I know quite a few and if you told them pick me some winners from these numbers you would be hard pressed to find guys go much over 55% over a full year of different sports. What sharps do though is have innumerable outs, offshore/locals/Vegas, and that is worth a lot more value than I think almost everyone betting today realizes.
3. People have touched on it and its very true. Just who is a sharp? How do you know? You could be book manager and think this guy you got isn't all that sharp because he isn't hitting with you that much, but that is just luck involved. If a guy is betting with 10 outs, chances are pretty good that one or two will make money off of him just as a matter of luck. The others might lose more than is expected. The only real way to judge a sharp is to talk to other books and pay very close attention to what he bets on and at what price relative to other key books.
4. Not so much that sharps are worried about their info getting out, its just it serves no purpose. I knew and spent a lot of time with many of the old school sharps in Vegas and most of them would openly talk about who they played and maybe some of the reasons why. Thing is that most of us when we talked didn't even bother with that. We talked big picture, much like this site does. To people seriously involved its not really about the basics of who to bet on a given day, its about whats going on and where things are going. Don't forget that if you are a winning player you are not picking winners, you are merely investing your money in spots you think have an advantage so you need to stay out of day to day thinking that I suppose a lot of posters wish sharps would talk about.
5. The edges you think sharps have access to really aren't much of an edge. Further a lot of the info is out there for you to find. I will tell you this, once again the secret to many a sharp is discipline and having lots of outs. If a sharp said that on here, people would say "yeah yeah, but who do you like in such and such game today".
6. Lastly the number of sharps is small and they come in all shapes and forms. Some are very publicity shy and want to stay completely off the radar, for strategic or just privacy reasons. It is true, the more someone boasts about how sharp they are, the more likely they are a fraud. A sharp is just someone that does his job well. Think about it, a good cop doesn't go tell the world "damn I am a good cop", he just shows up everyday looking to make things better for his city. Sharps are much the same, they don't see value in boasting, they just concern themselves with getting the job done right. Posting boards often are such a distraction full of directionless info that it can often be more hassle than value. Once again never forget we come here first and foremost because its entertaining.