In this issue:

• The "Kids These Days" Model of User Retention

• Tax Traps and Heterogeneous Preferences

• Software Eats Lines

• Number Cruncher Indigestion

• Edge

• The Other Last Mile

I'm doing a Callin interview with author Jimmy Soni tomorrow at 4pm ET/1pm PT. He and I will be talking about The Founders, his new book about the early days of PayPal. I highly recommend …