> nobody will RSVP because they're all waiting on each other to RSVP

The article discusses this. “Start by inviting your closest friends, get some yesses, then expand from there.”

The trick is that you already discussed the party with a core group. They are basically co-hosting the party with you. You already cleared the idea with them, heck throwing the party might even be their idea. So they won’t be waiting for others to RSVP. And then their yes-es provide the social proof to others that it will be a cool party and they too join saying yes. Thus the party grows like a snowball.

> a dedicated app for inviting people to the party is too much fanfare for my taste

It is not for you. It is for the party organiser so they don’t have to copy paste the same information to everyone (date, location, short description). It also sends reminders to people who want to be reminded.

> A good party fosters serendipity.

Yes. I agree. Serendipity at what happens at the party, who do you meet, what do you folks do or chat about. Not quite sure how a party invite ruins any of that.