I hope I'm not the only one who got the joke - I thought it was rather clever. Scroll down if you didn't get ChrisR's [link|http://z.iwethey.org/forums/render/content/show?contentid=164607|comment].
Rust is another word for Corrosion.
Corrosion.org can be spelled kuro5hin.org, AKA K5
rusty runs kuro5hin.org
Rusty reached his limits with trolls, so he stopped new user accounts from being created, as discussed [link|http://www.kuro5hin.org/story/2004/3/24/0502/96199|here].
ChrisR was drawing the parallel between zIWeThey and K5's issues with new user accounts.
Oh, why the move to Big Iron? Well iron rusts, so it seemed like the best forum for discussion of rust and corrosion (and admin gets crabby if Suggestions gets too far off-topic ;-)
(Who can't resist stating the obvious sometimes.)