Rush - how do you remember so many girls?

[sunandsand]

This may seem like a stupid question, but how does Rush work? Are there people in every sorority assigned to greet and talk with PNMs? Maybe people who might be considered to be the best judges of character? Are they usually seniors or do they encompass all years? Are they assigned to specific PNMs as recruitment continues (especially for Preference night)? And with a couple hundred women passing through your houses (more for larger schools I am sure), how do you remember the good, the bad, and the "really? she came through today?" well enough to decide whether or not to ask them back?