summarised badly from http://advogato.org/trust-metric.html
Advogato establishes trust between members using a certificate process. Each member can certify his or her trust of another member of advogato.org.
As each member trusts other members a graph/web is built up of who trusts whom. This graph is then traced from the seed member to every other member by the shortest route possible. The number of jumps between member is then used to assign each member a capacity:
1 -- 2 -- 3
Here 1, the seed user, has trusted the user "2", who in turn has certified the user "3". 1 (the seed) has the highest capability of 800, user 2 has 200 and user 3 has 50 (advogato.org has far more levels - new users will get a capability of maybe 2)
So, to progress up through the ranks of trusted users, you have to be trusted by higher and higher people. To do that in advogato.org, you either have to write good software or good articles.
There is a lot more to this process (security and network flow modelling), but I thought I would make sure I really understood the system before continuing. | 
