This is the Linaro cross-build daemon. It exists to cross-build packages in Debian and Ubuntu using various tools to show the current status of what works and what doesn't.
You can use it to see if a particular package you are interested in is already known to work, or to find packages to file cross-build bugs against.
Details on how this is set up are here.
To do your own equivalent builds follow these instructions
Status overview for each build flavour. These builds are run on the plain upstream archive, except arm64 builds which have a bootstrap repo added. The debian build uses emdebian.org cross-toolchains. It is currenty (feb 2013) stalled.