Also, Google+ is blocked at many workplaces (so's Facebook and Twitter), so there's quite a few Techmeme/HackerNews posts that are impossible to read at work. (Most tech blogs aren't blocked).

I think half the fascination with Google+ for people with lots of followers (e.g Linus posts semi-interesting stuff to his Google+ page from time to time) is that it gives people a relatively clean, vetted discussion board with "real" people, i.e. not trolls -- without much effort. (Ditto for Facebook except that it seems to be less optimised for long blocks of text.)