In this period we are developing something similar to a social network (where user authenticate themselves and are registered in the platform and communicate with other socialnetworks like Facebook, Twitter, Foursquare etc..).
It's been decided to use the Open Social standard in order to have a standard JSON format of communication between clients and server. These are the current specification in case you are new to it http://opensocial-resources.googlecode.com/svn/spec/1.1/Core-Gadget.xml
Did someone ever used this standard before? Is it a good solution? What could be the advantages of using this standard since the most important social network doesn't currently implement it (exception for MySpace and Linkedin)? Any past experience with this?
Actually I've used OpenSocial once, and while it seems a reasonable idea at first, my open social experiment turned out to be a failure
Personally I think the 2 reasons of this failure were:
The O.S. standard (as you anticipate in your question) is not used by the most important Social Network.. so, unless you don't have to build your own social network, I think it is pointless to respect standard while you can define a communication protocol which meets your needs.
The current libraries that implements O.Social are not completed and sometimes are missing some important features.
We used http://code.google.com/p/opensocial-java-client/ thinking that a lot of things were already implemented (for not falling in NIH). We were wrong! Since there is none who ever developed some library that convert Facebook JSON or twitter JSON in open social standard (at least 4 mounths ago we were unable to find it), and I've developed those by myself. In the end we decided to left this standard and we moved to a solution more adapt to our needs.