Old means that we have a newer version in Nixpkgs already. If there is a reason
for the old package to still exist, i.e. because some other package is still
referring to it, then Hydra will still build the package as a dependency, but
we won't want to build old packages on their own right.
By now, it happened twice that a commit broke GHC and thus all Haskell packages
we have in Nixpkgs. On such an occasion, I receive well in excess of 3000
notification e-mails from Hydra, and then I receive another 3000 e-mails after
the bug has been fixed. Under these circumstances, subscribing to these
notifications makes no sense for me.
svn path=/nixpkgs/trunk/; revision=33392