Plasmas shouldn't lay on their sides?

[JamesKurtovich]

Being relatively new to the HD trade, my first TV was a cheap obscure model (the cheapest at the time), 32" 1080i/720p LCD for $500 at Wal-Mart (SILO). About a month ago, on Black Friday, I bought a 50" Samsung and when loading it up, one of the associates told me that plasmas can be damaged if layed down on their sides. I had to lay it flat in my truck as there was no other way to transport it... seems fine. Works excellent. I've noticed that when I turn it off, if it's dark enough, I can see what was previously on the screen (disappears after 5-10 minutes). Upon discovering this forum, I see a "break-in period" recommended. Is it too late for me to try this?

Thanks guys. I love plasma... don't think I could ever go back to LCD.. but from what I hear, OLED is the new thing and it sounds really sweet.