True that, particularly on the meaningful conversation side of things. Like many, I initially approached G+ as a kind of Facebook. I focused on basically friends, coworkers, acquaintances - personal relationships developed through assorted means. That was neat in having a replacement for my Facebook account, but I kept on hearing about noteworthy commentary being posted via links to G+ on hn, reddit, etc so I started exploring with new non-friend circles.
After branching out to my immediate interest areas (tech), a little later I ended up adding Philip Plait (bad astronomy guy), Fraser Cain and other sciencey/astronomy folks. The amazing Hangouts that these folks do a number of times/week makes me feel really lucky to have access to such a resource. Certainly having some degree of access to experts in assorted fields is nothing new thanks to the internets, but G+ has, in my view, made such interactions far more accessible.
I can only imagine that there are other groups doing awesome things with G+ who I have not yet found.
The photographers seem to be having a strong community on G+ and G+ is the place where us amateurs can be exposed to their awesomeness. And talented those people are.
In the last few months, I have noticed many HN posts linking to Google+ posts. G+ is becoming a strong blogging platform and because Google is pushing rel=author so hard, soon it won't matter WHERE you wrote it (domain), it will matter WHO wrote it (author). That's why I see A+ bloggers adopting G+ soon.
I'd see'em in Google-themed subreddits like r/android pretty often which makes sense, but in regard to the more popular subreddits, they pop up every now and then in r/programming, r/atheism, etc. kn0thing submitted a post to r/technology the other day in regard to his plans to speak to the committee on SOPA and PIPA. I think I ended up following him on G+ after that one. I also vaguely recall the 'Comcast using tricks to raise rates' post also getting a fair amount of attention from r/technology
That said, I'm pretty sure it's possible to do a reddit search for submitted links to a particular domain if you're looking for more details. (I'm a little hesitant to link directly to a bunch of reddit pages here. Don't want to step on anyone's toes.)
Anyway, it's not like G+ posts are exceeding imgur links or anything. It just seems that based on my completely non-scientific observations, I'm seeing G+ posts linked more frequently than previously (or perhaps I'm just looking out for them more often ;)).
After branching out to my immediate interest areas (tech), a little later I ended up adding Philip Plait (bad astronomy guy), Fraser Cain and other sciencey/astronomy folks. The amazing Hangouts that these folks do a number of times/week makes me feel really lucky to have access to such a resource. Certainly having some degree of access to experts in assorted fields is nothing new thanks to the internets, but G+ has, in my view, made such interactions far more accessible.
I can only imagine that there are other groups doing awesome things with G+ who I have not yet found.