Guest: David Lieb, CEO and co-founder of Bump
Producer/host: Arman Suleimenov (
Mountain View, CA
December 8, 2011

Bump is one of the most popular free iOS apps of all time (more than 65 million downloads, 7th in US, 3rd in Japan). Bump ( is the mobile application which lets two smartphones to share contact information / schedules / photos / app recommendations / etc. by simply bumping phones together. After the recent partnership with PayPal, you now can exchange money using Bump. Bump is funded by Y Combinator, Sequoia Capital, Andreessen Horowitz, SV Angel, Ron Conway, Ram Shriram and the others.

Questions addressed in this interview:
What is Bump?
The origins of the idea for Bump
How to start a startup: 2 ways startups are formed
YCombinator experience: launching before applying
Make something people want
How did Bump look like on the YC demo day?
Challenges of the network effects product: from the risk to the asset
Thoughts on NFC (Near Field Communication)
Closest pair problem from Computational Geometry
Retention rate and usage across different features
Countries where Bump is big: US, UK, Japan
Reasons why Bump is the 3rd most downloaded mobile app of all time in Japan
Stats: the total number of downloads, the number of active users in the last 3 days
The key lesson learned as the first time entrepreneur
Technology stack: Objective-C, Java; C and Python on cloud servers
Hiring at Bump
Applications built on top of Bump API
5 whys: underneath any technical problem lies the human problem
Viral engine growth at Bump
Blogs and books: Paul Graham’s essays, TechCrunch, Ben Horowitz’s blog; ‘The Facebook Effect’, ‘Emotional Intelligence’, ‘Steve Jobs’
The vision for Bump

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