The UI for setup and editing is a bit nasty for now. Can be reached via 'Mirroring' tab in account settings, or from a link at top of subscriptions list.
Currently relies on the OStatus plugin to handle actual setup, parsing, and importing of feeds; to support more general feed formatting we may need some further work there to accept weird feeds.
Also requires an actual live subscription, but this could be changed in future. (Ensuring that PSHB feed subscriptions remain live even if nobody's directly subscribed might be tricky.)
The repeat style is our preferred method since it retains full attribution, but right now we don't handle repeats very well across site boundaries; when pushed out to Twitter or to other StatusNet instances via OStatus, currently we end up losing some of the data and can end up with the 'RT @blah' version.
WARNING: There's no loop detection yet; it's most likely possible to set up a fun loop of profiles repeating each others' stuff forever and ever and ever and ever...
Siebrand Mazeland
Brion Vibber