- Getting a meal at your favorite local restaurant for half the regular price (Groupon)
- Seeing the hot girl in your class' private collection of photos (Facebook)
- Finding who you know, that might know, someone at a company you are targeting (LinkedIn)
However, did these companies start life tackling these problems -- did they explicitly know that these were the problems they were addressing? It would appear the answer is not...
- In the case of Groupon, the team was initially working on group-giving (The Point). They eventually pivoted to what people seemed to want to use the site for - group buying.
- Facebook was initially just a Facebook for Harvard. Quickly, users were uploading their other pictures.
- LinkedIn - I suspect - initially grew out of people wanting to show others the high-status people they are linked to.
It just goes to show you what happens when you listen closely to users and pivot to meet their needs.