It is true that there was a substantial delay before G+ was made a public external platform (there were initially some external, selected partner, integrations), but G+ has been a public external platform for some time.
> Google has offered no useful APIs for it
"Useful" is subjective, of course, but they offer a fairly extensive set of G+ platform APIs. [1] It's true there isn't a write API for the Facebook-style news feed, but that feed isn't central to G+-the-platform, only to G+-the-product.
Where's my access to pushing content from another network or platform onto G+?
Other than Data Liberation, were's my ability to extract content from G+?
It's a fucking silo. Always has been.
There's a read API for activities, but its not RSS/Atom.
> Where's my access to pushing content from another network or platform onto G+?
Push it from the integration app as App Activities using the Moments API.
> Other than Data Liberation, were's my ability to extract content from G+?
There's read APIs for the various kinds of Google+ content.
> It's a fucking silo.
Well, except for all the ways to get content in and out of it, sure.
I've looked for push tools and haven't found them.
Links on this stuff you're referring to?
It's still a fucking silo.