I agree with Atrios, the leader of the country should have at least some basic knowledge of computers and the internet. Or at least use them once in a while. But John McCain admits he has no idea how to use a computer and, I assume by extension, no practical understanding of the internet. This maybe doesn’t completely and totally disqualify someone from being president in the 21st century, but it sure should be points off. See the video of McCain’s remarks here.
The good news is we have photographic evidence McCain does know how to use, or at least talk on, a cell phone.