Short answers, pulled from the story.
An IP address is a numerical label assigned to a device connected to a computer network that uses the Internet Protocol. It serves two main functions: identifying the network interface of a host and providing the host's location in the network so that a communication path can be established.
IPv4, first deployed in 1983 in the ARPANET, uses a 32-bit address format that limits the address space to approximately 4 billion addresses. IPv6, formally designated in 1995, uses 128 bits and provides approximately 3.403 undecillion addresses. Both versions are still in simultaneous use today.
IPv4's 32-bit format creates a finite pool of addresses, some of which are reserved for private networks and multicast use. Rapid internet growth in the 1990s and 2000s consumed the available public address space, leading to IPv4 address exhaustion across the 2010s.
A static IP address is configured manually and held indefinitely, changed only by deliberate action. A dynamic IP address is assigned automatically each time a device joins the network, typically by the Dynamic Host Configuration Protocol, and carries a lease with an expiration period after which it may be reassigned.
The Internet Assigned Numbers Authority manages the global IP address space and distributes blocks to five regional Internet registries. Those registries allocate addresses to local registries, including internet service providers and large institutions, within their respective regions.
It depends on the jurisdiction. In March 2024, the Supreme Court of Canada ruled that IP addresses are protected private information requiring a police warrant. The European Commission treats them as personal data under the General Data Protection Regulation. In the United States, the California Consumer Privacy Act protects IP addresses only when they can be linked to a specific consumer or household.