Is there a backup/replacement for the Complexity Zoo?
I cannot remark on whether the Zoo has a continuous existence on the web or elsewhere. However, there are still some proto-Zoo and Zoo-derived resources available on the web.


There seems to be a copy of at least an earlier incarnation of the Zoo on Greg Kuperburg's UC&nbsp;Davis website.
A Latex/PDF version of some state of the Zoo written by Chris Bourke seems still to be available on his webspace at the University of Nebraska–Lincoln.


Other sources on the net seem to be links to the first (or to the URL to the stanford.edu subsite), or pieces of the second.

It is worth noting that the entire qwiki.stanford.edu subsite seems to have disappeared, and that google searches for "qwiki", with or without specifying "stanford", either yields references to a multimedia product launched in January of last year, or produces the typical spoor of SEO companies trying to leach off of online resources.