As announced in the Debian Project News of September more mirrors have recently joined Debian's mirrors network. Two more have been added since that issue of DPN was released, and about four more might be added any day now. Many thanks to those sponsoring them!
The mirrors redirector has also received some improvements, and around 2.5 million requests a week.
Among the improvements, users of teredo and 6to4 tunnels are now handled as IPv4 users. Not only it gives them access to a wider range of mirrors, but it also avoids the tunnel overhead.
Another improvement is the prompt detection of mirrors that drop architectures without prior notification. This is thanks to a new version of ftpsync, the standard and recommended tool to create Debian mirrors suitable for Debian's mirrors network.
As more mirror administrators upgrade to the newer version, or switch to it, http.debian.net and other tools become more reliable: they no longer need to perform some checks and hope the results mean the mirrors actually include the architectures they say they include.
In this regard, http.debian.net is an improvement over debian-installer's mirrors selection menu: not only it chooses a mirror that is close to the user and up to date, it also ensures the mirror provides the files for an architecture even after the installer image has been built. debian-installer's mirrors list is static and hard-coded into the installation media.
There's more to come, stay tuned.