RSVP'd
I want an online invitation system where I can set a "Max RSVP Number" so I can put a ceiling on the number of people who come to events that I host. Honestly, I *want* to be able to invite the whole world when I hold desirable events, but it's a matter of logistics that "poker night" can't accommodate more than 8 people and "homemade pizza/sushi night" tops out at 24 and 12 (respectively) based the amount of space needed for eating.
As a host... it's frustrating to only invite a dozen people to an event (like "poker night") where you want between 5 and 8 people to show-up. Too many times I've had 7 people confirm and then three of them drop-out 4 hours before the planned event (luckily, Wii has lots of 4 player games for when this happens). I've also had 9 people confirm and show-up (too many!). For the times where 4-5 people confirm, I like to invite an extra 6 people two days before the event to get closer to the 7-to-8 sweetspot. But the point is, if not for concerns of having too many people, I would have preferred to invite those people at the beginning because I'm not the sort of person who likes playing favorites.
For people who try to RSVP after the "Max RSVP Number" is reached, they can join a waitlist. The optimal situation would be to have a system that automatically e-mailed all the waitlisters when somebody un-RSVPs so they could get a chance to add themselves to the RSVP list.
To my knowledge... no such sophisticated system exists and yet I think this would be a killer feature for lots of people besides me.


