If you're interested in building and expressing the information of a web application which contains social networking features, Activipy may be a great place to start.
Some things I think are interesting about Activipy:
: - It wraps ActivityStreams documents in pythonic style objects - Has a nice and extensible method dispatch system that even works well with ActivityStreams/json-ld's composite types. - It has an "Environment" feature: different applications might need to represent different vocabularies or extensions, and also might need to hook up entirely different sets of objects. - It hits a good middle ground in keeping things simple, until you need complexity. Everything's "just json", until you need to get into extension-land, in which case json-ld features are introduced. (Under the hood, that's always been there, but users don't necessarily need to understand json-ld to work with it.) - Good docs! I think! Or I worked really hard on them, at least!
As you may have guessed, this has a lot to do with our work on federation and the Social Working Group. I intend to build some interesting things on top of this myself.
In the meanwhile, I spent a lot of time on the docs, so I hope you find reading them to be enjoyable, and maybe you can build something neat with it? If you do, I'd love to hear about it!