The answer appears to be yes… sort of.
Since Open Graph is an open protocol of sorts, it’s not meant to be Facebook specific. And it appears that while not all vendors may respect the tags yet, most do.
Take Pinterest for example. If you use the “Pin” button provided by AddThis, it will use the “og:image”, “og:description”, and “og:url” tags. However, through my own experimentation, the Pinterest bookmarklet and adding directly through their site does not appear to use the open graph metadata.
As for Google Plus, that’s answered here. Basically, they give “schema.org” the highest weight, but if they do not exist they will fall back on open graph tags, and if they do not exist they will fall back on page content, like “title”, etc.