If a lake is producing limits I will bet you anything, anything, that the fish are not biting EVERYWHERE on that lake. Good luck in finding them on a MULTI ACRE lake when you hear of a spot like a bridge (which always holds crappie) which has fish at it at that given time.
I have never seen nor heard of people fishing out a lake because someone posted "The fish are biting good at this bridge at this given time"!
With that logic NO ONE should post ANYTHING about ANY lake in ANY forum for fear the fish might get all taken.
I am not going to worry about a little spot on a lake causing the fish to disappear or shrink in size due to my posting to help someone else have a good day of fishing at a single spot no more than 50 feet square.
And when I say "good day" fishing, I mean about a day or two is about what they will get before the fish move on to another spot and can't be found there again!
I am sorry but I just cannot believe that posting in any forum causes fish to deplete any more than they would from normal day to day fishing. Your local wildlife department that monitor lakes and can give you reasons for fish size reduction or depletion. I would venture to bet also that they will not say the fish are reduced in size "from fishermen reading forums and fishing the lake out". They have no proof and neither does anyone else. If there was proof then it should be voted illegal in some states.
I personally feel it's a pride thing.