The Death of the R.S.V.P
nytimes.com
nytimes.com
I do agree that not RSVPing and still showing up is a breach of etiquette; a non-response ought to be treated as an implicit no, imo. But to help that along, it does pay to make sure to explicitly request an RSVP fairly prominently. Among the flurry of emails I get, an invitation that requires an RSVP, versus an open invitation that I can just show up to or not, aren't always that easy to distinguish (for example, I don't have to RSVP to show up to visiting speakers that my university sends me email "invites" to).
When I'm having a dinner party, or even a small party, I still call everyone personally. The difference it makes to getting people to come is enormous, it makes people feel wanted. Failing that, a personal email (rather than a batch send) also makes a big difference.
I agree that this works both ways - people are getting lazier at inviting people in the same way people are getting lazier at responding.
1. Needs universal login features that are amazingly simple.
2. Needs a Google Mapping system with automatic directions from your Geo or IP address general location.
3. Needs to exist on a single page in a very simple non-tabbed view.
4. Needs to be extremely sharable.
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5. Use Disqus for commenting.
6. Take a leaf from Vark and make it integrate with Instant Messenger, SMS, and E-Mail.
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Revenue? Perhaps charge for repeating events or more events than 4 per month. Something like $1.00 per repeating event, or 3 events.
Edit: Also, there are plenty of sites that do this, I would suggest starting with a facebook app and keeping some sort of score, aka number of events hosted, average gathering size etc. You could even add some sort of avatar based on unlocked achievements.
As a young person, I read this as: I'll come to your party if nothing better comes up.
Some non-tech people said to me that they couldn't figure out how to RSVP to Google Calendar invitation (link is provided in email).
Social aspect plays when other people see who and how many people have responded. Some people don't want to RSVP first because they don't what to seem like desperate people sitting at computer all the time. Some people don't want to RSVP because everybody else includes some witty comment and they can't invent anything witty enough. Some people don't want to RSVP 'No' and think that no answering at all is less antagonistic.
The Automated Invitation sites are very unattractive to me not for ease-of-use, reasons. I don't use those channels because to do so is not only sending an RSVP to the host, it's also telling the website that you'll be attending, as well as their advertisers, their business partners, and other downstream marketers, etc.
Let's not confuse social conventions and etiquette with usage of the Ad Revenue oriented vehicles through which were asked to attend.