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 ;)).
