Dated technology

Very few people outside the technical community are aware of the future problems posed by the Internet's archaic technology. It was originally designed for a small number of research institutions to share research data, and was never intended for the multi-billion user behemoth the modern Internet has become.
One serious problem is that the IP address (a unique number assigned to each Internet computer, functioning much like a street address in the real world) will run out eventually. Despite an estimated world population of over six billion, there are only a little over four billion different IP address combinations possible under the current system — see IPv4 address exhaustion for more information. This also doesn't take into account the fact that there is not a 1:1 person to computer ratio in current computerised countries, where many people will have a desktop machine at home, a laptop machine for on the go, another desktop machine at work, and an e-mail mobile phone, all requiring their own IP address.
This could pose serious problems in the future as more and more nations expand their computer infrastructure (the vast majority of the world's population does not currently use the Internet, that's the so-called digital divide) and even now efforts are proceeding to find new ways of running the Internet. The new version of the Internet Protocol, IPv6, which expands the address space of the Internet, is one proposal for how to deal with some of the technical problems caused by the growth of the Internet.