Online reviews of local businesses
Noticed one feature showing pull: Noticed people using the product in a surprising way (leaving reviews on their own), and went all in.
Tool to automate emailing friends for recommendations
Lukewarm interest
https://web.archive.org/web/20140817232337/http://archive.fortune.com/magazines/fortune/fortune_archive/2007/07/23/100134489/index.htm
“It went nowhere. But the co-founders noticed an interesting tendency among the early users. People were writing unsolicited reviews of their favorite businesses just for fun. So Yelp switched tack. ‘I remember the moment that Russ said, “There should be a way for you to write your own reviews without asking questions,”’ Stoppelman recalls.” —Fortune
9 months
Recommendations as a concept