Of course you can mount your TV over the fireplace.... you can mount your TV anywhere you please. This is the internet, however, so for every 1 satisfied customer with their TV mounted over their fireplace you are going to find 1 person who will tell you that your TV will instantly combust if you mount it over the fireplace.
I have a buddy with his mounted over a fireplace and he is happy w/ it. He does, however not use the fireplace. If you use the fireplace all the time I would probably not do it.
We just burn a starter log in ours every once in a while so we are still considering it because the mantle is so high.
From that article: This has always cracked me up:
"When mounting a plasma over the fireplace, there is a real risk that your plasma will be too high for real comfortable viewing while seated, especially if the mantel is a bit higher than average.
In these circumstances, it is best to make use of a tilting plasma TV wall mount. Tilting wall mounts provide for a change in the vertical angle of view"
How exactly does a tilting mount help with the fact that the TV is up high? I'm fairly certain that you still have to look up to the same height if it's tilted