How many people can read hex
if only you and DEAD people can read hex?

This is a joke I heard years and years ago that stuck with me.

The solution is obviously (to some) that dead is a valid hexadecimal number as hexadecimal - which is base 16 as opposed to base 10 for "normal" decimal numbers- uses values 0-F ( 0 1 2 3 4 5 6 7 8 9 A B C D E F) for each position and DEAD + 1 = DEAE which is 57006 (57005 + 1) in decimal. So that is how you convert 0xdead to decimal. 0x1234A is a common notation for hex so things starting with 0x and capital letters is a big clue.

Nerd humour..

This domain name is a play on the same theme as badcoffee is both valid hexadecimal and I as many in the business have a deep and long relationship with coffee.

Link to wikipedia and decimal.info for a few more tips. Below is a good video by Numberphile on the same subject.