If someone shares a link to a public Facebook post, do you consider it an attempt to get you to share stuff on Facebook? I find it odd that you assume someone sharing something on Google+ is an attempt to get you to use Google+ rather than an attempt to share the content with you.
I believe he's talking about the fact that, at the end of the Zerg Rush game, Google prompts you to share your score on Google+.
Thanks for pointing that out, I didn't play until the end of the game.