Regarding Orkut, I am surprised that nobody noticed yet anything about its trust metrics or lack sucheof. I am fascinated with Raph's research, and indeed it's the only reason I stay with Advogato. So, it was natural for me to join Orkut, just to check it out. We all know that Google uses PageRank. So, I added two and two, and got ... zero? I am terribly disappointed so far.
It appears that Orkut does not perform ANY interesting computations. It is purely a database of nodes and edges. The welcome page displays a fractional number, captioned "Average Path", but there is no explanation anywhere how it is calculated and what it measures.
And they could have done so much more with it. A trivial thing to do (or, rather, a trivial application of non-trivial math), would be to calculate trust, using user as root, and sort membership lists in communities according to decreasing trust. I am talking about Raph's trust, rather than Orkut "trust". They reused the word for one of three local metrics they allow to enter.
In any case, even if Orkut developers decide to pull their heads from their asses and use their own company research, I highly doubt that they'll publish the code. In the same time, mod_virgilie is open source.