Challenge to Metcalfe’s Law

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There's a fascinating short article in IEEE Spectrum this month summarizing an interesting debate about Metcalfe's Law.  Metcalfe's Law says that the value of a communication technology grows with the square of the number of users of that technology.  Informally, the rapid growth is because the value grows with the number of users with whom you can communicate.  

The debate started with a July feature article by Briscoe, Odlyzko, and Tilly that argues that Metcalfe's Law overstates the growth rate.  The heart of the argument is that the growth is actually proportional to the value of the users with whom you can communicate, and that the value of being able to communicate with users probably falls off like a power law function.  (Many features of social networks fall off with a power function.  Some people believe that this is a fundamental law of social networks, that separates them from other types of networks in which value falls off more slowly.)  If the value of new people to communicate with falls off as a power law, then the value of the communications network scales as n * log (n) — much, much slower than n squared.

There's now an interesting debate going on at VC Mike's Blog on this issue.


Chipmark Project

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Chipmark is a fun project in which a group of University of Minnesota students have worked together — with advice from me — to build a distributed bookmarking system.  Check it out at!  It's wonderful if you use many different browsers in your day-to-day Internet life, because you can share the chipmarks among the browsers effortlessly.  The main interface is through a browser plugin, for either Firefox or Internet Explorer.

The other cool feature of Chipmark is that three teams of 12 students each have worked together over the past three years to do all of the implementation themselves.  It has been a great learning experience for all of us — and I expect to see them doing great things out in the world as they graduate.

URLs Matter in Social Bookmarking

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Interesting article that argues that getting noticed in social bookmarking sites is based on your apparent popularity. The difference between being in the top 10 list and not in the top 10 list can be huge; one important factor even for very popular sites is making sure everyone bookmarks your site by the same URL. The article mentions a couple of ways of doing this.