Dr.Z and CJ, Are you two related?
Anyway, you know IPs? 172.452.123.432, for instance? Four sets of three decimal numbers, which represent the actual binary address.
Each computer on the internet- well, that is, at least every modem or router or other gateway to the internet- needs to have a unique one.
Now, 999,999,999,999 computers sounds like a lot, but it isn't quite distributed that way. Y'see, when they where first starting up, they gave out IP addresses like crazy. A trillion here, this comany gets 500 billion, and so on. And a great many are already locked off; 127.xxx.xxx.xxx can't be used by the internet, along with several others, because of various inferstructure reasons.
When all is said and done, a very small number of IPs remain, and the consumption of that namespace is increasing as more people try to get online.
Don't belive me? Check out
The Wiki.
Of course, they had a plan to fix it- a new system you may have heard about, IPv6- it's just that it's been around for half a decade and none of the ISPs have gotten around to implementing it. Odds are, they won't even get started until the whole system implodes.
I rather like IPv6. It's eight sets of four hexdecimal numbers, giving us FF,FFF,FFF,FFF,FFF,FFF,FFF,FFF,FFF,FFF,FFF possible addresses, or 2
128 addresses, and lets some lucky internet guy get DEAD.BEEF.BABE.CAFE as their IP.
239 days to go now...