A rewrite from scratch of BIND 9 for OpenBSD and FreeBSD. [edit]
A new player has entered the arena: Unbound is an open-source DNS server written, maintained, and distributed by a consortium of Internet companies that specialize in domain-name sales and management (NLnet Labs, Verisign, Nominet, and Kirei), and released under the BSD license. As Mike noted, Unbound has the potential to challenge the DNS monoculture.
With gazillions of sites on the internet, one of the key pieces of infrastructure is the lowly DNS server. If you think about a world where you're required to locate servers by IP address instead of name, you'll quickly appreciate DNS.
In the world of DNS servers, BIND is dominant, running over 70 percent of all DNS servers according to a recent survey. Now a relatively new entry in the market, Unbound, wants to change that.