How is traffic calculated?

I know the basics of how traffic is calculated but maybe someoe with more experience can shed some light on this topic for me. The reason i ask is that im helping a friend get hsi club established yesterday his traffic was 5579 and he had a blow out event with over 70 people last night and 2 medium event during the day. today his traffic is at 0. what could cause this and what factors into thee traffic calculation.

1 point per minute spent on the parcel, per avatar other than the owner. Points go stale after 24 hours.

thank you yumi any idea on what would cause the traffic to go to 0 since theland was flooded all night with people