I see one project as a luxury. It has to be interesting and you have to have ownership for one project to be the right answer. You also need a way to pay the bills. When working for someone else, my magic number is two so you don't end up getting stuck and waiting.
Cool idea but not for me. There's something about voluntarily following a Gantt chart for something I consider a hobby and an outlet for creativity that spooks me.
I remember really wanting to like B&N e-mails. The thing that annoyed me was that they would always pretend to have great deals just for me. Then I realized that all of their 20% off deals would still cost me more than buying the book from Amazon at their normal price. Plus as alluded to in the article, I never saw any books/movies/CDs that jumped at me. I finally gave up and unsubscribed.
I love Border's e-mails on the other hand. They send me coupons varying from 10%-40%. I think that they do data mining to figure out which e-mails I respond to. I'm trying to teach their learning algorithm that I only use 40% off coupons;-)
I know the founders personally and definitely agree that it was one of the best (or at least most useful) YC startups. I don't know the whole motivation behind it, but I know that the founders decided to pursue other paths and to stop actively developing new features a while back but will keep the site running in it's current state. I still use the site to brainstorm whenever I start a new project.