Gigaom presents a comparative overview on the portability initiatives recently taken or promised by MySpace, Facebook, and Google. Neither truly open nor entirely closed, they fall somewhere in between control and ultimate user freedom, and Gigaom gives us some criteria to judge the degree of openness.

Stacy writes:

“There’s open source (really open in that anyone with knowledge can participate in how the code evolves), open standards (open only in that anyone can participate using a pre-defined version of the standard), and open APIs (open in that anyone can take the pre-defined standard and build something for a closed platform such as Facebook). Knowing this, the efforts to open up a user’s data on a social network (their social graph, if you will) by these three companies falls somewhere between an open platform and an open standard.”

table via GigaOm