Round robin is more of an intro to the sororities at my school. All the organizations gather in a very large room with tables and flyers and PNMs are herded in and make their way around to everyone themselves. I guess it can be kinda like a round one because we can talk to the girls all night if we want to and show them our table and such. However, the next round is called Round 1 and since it is informal recruitment, PNMs decide which organizations they'd like to visit and go to the respective parties.
Its kind of hit or miss though because they aren't mandated to see every sorority during informal recruitment...so if you don't hand your flyer to a girl, she's not going to know anything about our Round 1 (like when is it, where is it) or anything about your organization for that matter! :\