I knew I liked Joel. Two more examples more germane to my world:
1) Bike parking. Want to pay for monthly secured parking in Harvard square? No problem. Want to pay to park your bike in the same garage below your building? Sorry, the rack's for residents only. Currently battling with this work after a year of happily parking my daily commuter indoors.
2) Pharmaceutical markets. Dr. Waldfogel mentions drugs as in the much-ballyhooed genomics revolution, but that's years off and going to be incredibly costly given current drug development costs. What we do know about drugs is that they are targeted towards the problems of the developed world, despite the vast majority of the world's disease burden residing elsewhere. We pour hundreds of millions into Anthrax, but virtually nothing into developing a Malaria vaccine.

Nothing much to say about the XO/OLPC, except that I held one before I left for Ghana and found it cute and well-designed. Given that they're building an infrastructure around it, I think they'll do just fine on their own merits.

Ari