Not at all, there is no all-or-none proposition. One can participate on Google+ while simultaneously participating in other social communities. We're both doi

Not at all, there is no all-or-none proposition. One can participate on Google+ while simultaneously participating in other social communities. We're both doing it right now even! It's completely analogous to real life. You interact with different groups in real life differently (your coworkers vs. your dungeons and dragons friends). Some of the people you interact with in real life know your real name and some do not. You're free to make the decisions of how you handle your identity.