Moth3r said:
It's not a myth - at least, it might not be a problem on a high end Kuro, but I assure you on my entry level Samsung panel (bought in 2008) I get traces of game score counters, or that bloody CBeebies channel logo, showing up even the next day.
The worry of permanent burn was enough to make me turn the contrast right down on the Wii input.
The manual for this panel has screen burn warnings on the front page, and a statement to say that screen burn is not covered in the warranty. The menu also has several options for avoiding or rectifying screen burn (a whitewash, a b/w scrolling pattern, options to pixel shift a PC display at periodic intervals, and for setting the brightness of the "windowbox" bars when displaying 4:3 material).
Samsungs are notorious for image retention. The point is, if it's not permanent, it's not burn-in. I always recommend against Samsungs for anyone looking at plasma because their image retention problems cause people to freak out. There's something about their electronics or panels that causes them to have noticeable problems in this area.
Like I said, my Panasonic plasma, a 2008 model, never exhibited image retention beyond a few seconds in length in the year that I owned it--even after day-long gaming sessions--and it lessened as it aged. There are plasmas at every large retailer that run for 12 hours a day with no hint of burn-in. While LCDs don't have this problem, most are deficient in so many other areas that anyone interested in great image quality shouldn't bother with them.
I worked at Panasonic for years. The engineers deemed the plasma burn-in warnings unnecessary once phosphor half-life had reached the 60,000 hour point, but the legal team wouldn't let us remove it from the manual.