What's the deal?

[AXO Alum]

Quoted from another thread:
"...big, popular sororities (Kappas, Tri-Delts, Thetas)..."

Neither of my schools had any of these groups that everyone talks about being so big and popular. My undergrad college had:

Alpha Chi Omega
Alpha Xi Delta
Delta Zeta
Phi Mu
Zeta Tau Alpha
Alpha Gamma Delta

My grad school had:

Alpha Chi Omega
Alpha Delta Pi
Phi Mu
Chi Omega
Sigma Sigma Sigma

Is it because I live in the southeast?? I know that this past spring according to the NPC that Alpha Chi Omega is a Top 5 sorority, but no one seems to post much info about us (or any of these other groups for that matter)! I just wondered if its a regional breakdown or just that you all are attending much bigger schools. Just wondering!