Recruitment is year round.
Take a look at the "more successful" groups (however you determine success, be it size, brother/sisterhood, awards, etc).
Chances are, those orgs are present at major and minor events, participate in other clubs/sports/orgs, hang out together, wear their letters (free advertising!!), study together, etc. It's simple marketing. The more "impressions" they make (like internet ads), the more people know of them. The same goes for poor reputations.
Recruitment is more of a "telling" than showing. It's the every day stuff that "shows" people who you are. That's where the real work happens. Even if recruitment happens before school starts, PNMs (or whatever you call them in fraternities) will see you out and about.
PS: advertising for rush in your siggy here at GC won't really help you out. And your tagline - "A powerhouse of excellence" - doesn't really say anything.
I know that fraternity recruitment operate differently, but the more people who know (good things) about you, the more people you will have to choose from. (And it's not always about size.)
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