Last modified: 2012-08-23 17:45:45 UTC
Any search (on the EN wiki main page) that start wiki: (note the colon) direct to the external site http://c2.com/cgi/ Eg. Search for "wiki:reference" directs to "http://c2.com/cgi/wiki?reference"
This is correct, see [[Special:Interwiki]] for the list of interwikis. wiki: is one of them since the beginning of time and won't be removed in default MediaWiki nor in our [[m:Interwiki map]].