I think that all the movement amongst all of the houses is a relatively new thing. In the 10 years I was a member of/active alumnae of MSU's Greek system, there were very few moves. (I'm hoping all of the house jumping isn't a sign of instability in the Greek system - I'd like to have my chapter come back sooner rather than later.
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Delta Tau Delta is no longer listed on MSU's Go Greek website - I would guess that means that the chapter isn't active anymore, but I don't really have any details of course...just their absence from the website. (I always think of 330 N Harrison...next to SAEs...as the Delt house.
According to the website though, Sigma Pi is there now.)
I brought back 2 boxes of college mementos/stuff from my parents' house recently - my mom found them while she was cleaning out the basement. In it, I found my rush booklet from when I went through in Fall 1992, and also a fraternity rush booklet from 1992. Too funny! Now that I know about all of the housing moves that have went on recently, it would be interesting to flip through those books and see where everyone was back then!
(BTW - I have a retroactive recruitment thread going in the recruitment stories forum, since I found the booklet/my notes. Keeping the recruitment thread junkies entertained in the off season.
Knowing what you know about the locations of the houses on campus, you could probably figure out what I mentioned about certain houses being at a disadvantage during Phase A. I'd elaborate, but don't want to spoil the surprise for anyone who might be digging for clues right now.)