I came across this blog post about a week ago. It's like the perfect addendum to The Alliance, a book that I would describe as must read. This piece is great, another must read. One of things that I loved the most about it -- glancing back at it after sending the link to a colleague, I noticed the line at the beginning of the post letting you know about how long it would take to read it. The only thing it missed was the "your mileage may vary" caveat.
Here's the link: 10,000 Hours with Reid Hoffman: What I Learned