Airbnb: nights booked
Why it works: A night only counts when a guest pays for a stay and a host gets paid for it, so the number goes up only when both sides get something. Airbnb still lists it as a key metric in its S-1 filing.
What it really measures: whether trips actually happen.
How it can be faked: Airbnb could discount cheap long stays, or push the listings that get booked most even when they’re bad. Cost per night would go up. But guests who have bad stays stop coming back, and this number doesn’t show that.
Facebook: 7 friends in 10 days
Why it works: Chamath Palihapitiya’s growth team compared people who kept using Facebook with people who quit. The ones who stayed had usually added seven friends within their first ten days. He called it “a very elegant statement of… core product value.”
What it really measures: whether your feed has enough people you care about to make you come back.
How it can be faked: Facebook could import your whole contact list, send spammy invites, or suggest people you barely know. You’d hit seven friends, but your feed would be full of strangers, and you still wouldn’t come back.
Slack: 2,000 messages
Why it works: Stewart Butterfield said a team that has sent 2,000 messages has “really tried” Slack, and 93% of those teams kept using it. For a 50-person team that’s about ten hours of chatting. For a 10-person team it’s about a week.
What it really measures: whether a team has moved its real conversations from email to Slack.
How it can be faked: Bots and app integrations can post 2,000 automatic alerts without anyone typing a word. When the team hits the number, they can mute the noisy channels and go back to email.
The fix
None of these numbers causes success. Each one just tends to show up alongside it. Some thoughts:
- Nights booked, plus guest review scores
- Friends added, plus how often people come back
- Total messages, plus messages typed by real people
