I've just been looking at https://code.google.com/p/google-plus-platform/issues/detail?id=612
It's asking for an RSS/Atom feed for +1s. I'd certainly like Atom, but be happy even with just JSON.
Then it occurred to me that there's no API for the data on the other tabs of a person's profile, AFAIK. Is that right? So there's no API for Photos, Videos, +1s, Reviews for a specified person.
I still think the +1s tab ought to include +1s on the G+ platform, but regardless of that, there should be API access for data that's publicly available in the web view, shouldn't there?