Social Trust Based Transactions in Tanzania

These are keys to my Lexus 4WD and my 3 bedroom apartment with a view of Mt Meru. I haven’t signed any papers so far. And hardly fronted any money.


  • 8am – I text a guy that rents out cars.
  • 10am – he shows up at my door, hands me the keys and leaves. I ask, when do I pay? He says you can pay me later.
  • 5pm – I grab $$ from an ATM and pay him, along with a copy of my passport.
  • Done.


  • 5pm I stop by to take a look at a house (along with many others)
  • 8am (next day) I decide that’s the one I want
  • 4pm I show up with my stuff and am handed a key to a just cleaned house. When do I pay you? He says: today I’m busy. Tomorrow I am going somewhere. How about the day after?
  • So I will pay him in 2 days.

In Tanzania, trust is important. Relationships matter. The system doesn’t require you to distrust each other. Social reputation systems, and people’s reliance on them, remove the friction (and extra cost) associated with doing things more formally.
Western systems, however, are more universal. Not relying as much on social systems means there’s less biase, better exception handling and more scale.
As technology-mediated reputation systems get better, successfully avoiding all their traps and pitfalls, we can expect more Tanzania style personal, human service at western style scale and access.

Spin is an awesome touch video chat

Just tried Spin and was pretty blown away by the experience and the polish. Video chat with 10 people, no sign up needed. Watch videos together, annotate over live video, throw tomatoes, watch pictures and albums together etc. Quite the complete package.



Thoughts on the Trayvon Martin case

Please listen to this audio clip before you continue.

This is a picture of a glacier on Mt. Kilimanjaro which I took when I was there last year. It clearly shows that the glaciers have shrunk in the past years. I believe climate change is real. I believe at a minimum some amount of it caused by humans. The popular documentary “The inconvenient Truth” uses Kilimanjaro as a poster example of climate change. Makes sense? Unfortunately that is bull shit. Scientists have shown that the shrinking glaciers on Kilimanjaro have nothing to do with climate change. Even though climate change is real, Kilimanjaro is a bad example because it doesn’t apply here.

Kilimanjaro glaciers

When we believe something strongly, we are always looking for facts that validate our assumption – that’s basic human nature and scientific experiments show that we are likely to accept something that confirms our hunches than something that challenges it. Using Kilimanjaro as an example of climate change is an unfortunate waste of energy and detracts from actual facts that should instead be considered.

When I first found out about the Trayvon Martin incident I was outraged that they hadn’t even filed charges. I joined in to the Internet activism and was happy to hear that 45 days later they did file charges. I admit I didn’t watch the trial closely but was confident all along that Zimmerman was caught red-handed and of course he will be found guilty.

Continue reading “Thoughts on the Trayvon Martin case”