The goal is to gather as much information as possible without being a burden on the user. Right now the required fields are minimal, we just wanted people to use the system and we would worry about the details later. It has worked, year after year events submissions have grown exponentially.
So we made it a month, its great to see the readership grow. This week has been one of getting things done and blog neglection. The articles of the week reflect the same mentality in the blogosphere (lolz at the busswords).
Last week we sent out one of these emails, it was purely information regarding litter and cigarette butts on campus. Since there was no immediate action from the user it was difficult for us to track how effective the email was. So instead we measured how many users actually opened the email and viewed the images.