We've all been making fun of the iPhone 4 antenna problems for quite some time now. You know the one, where left-handers loose signal strength when they try to actually talk on their iPhone 4's.
It turns out that the iPhone 4's "unique new antenna design" may not be the cause of the problem after all. The electrical conductance of human skin combined with the signal blocking ability of the human body can combine in a sort of "perfect storm" which can cause a dramatic drop in signal strength. Unfortunately, the iPhone 4's antenna design seems to facilitate the conditions needed for this "perfect storm".
That doesn't mean that other phones are immune. Take, for example, my Nexus One running the latest radio from Korea. As the video illustrates, holding the phone "just right" causes a near-immediate drop of two bars -- half the signal strength!
After some experimentation I was able to figure out just how to hold my Nexus One to cause the bars to drop by one or two at will. This may add some credibility to Steve Job's statement that "you're holding it wrong". Then again, I had to try dozens of different "holding techniques" in both hands -- which took about 20 minutes -- to find out exactly how I needed to hold the phone to replicate the "death grip". (Maybe it doesn't give him that much credibility after all.)
What this does show is that the human body does a good job both conducting and blocking electromagnetic signals. If you're experiencing a drop in bars, using a Bluetooth headset may be your best option -- that way you don't have to touch the phone at all.