The answer is: No. A CFO should not be on Google+ today.
There is an exception to my answer. If you are a CFO that has mastered LinkedIn and you blog and tweet, go right ahead into the new world of Google+. If however you do not consider yourself social media savvy, make the best out of the (I can’t believe I’m saying this) old world social media tools.
As CFO, you’re a busy person. If you are going to spend time on social media, spend it where the market is mature and defined. Google Plus is so brand new, that you may not know what you are getting yourself into, few people are true experts that can guide you though it even if you wanted help, and you may mess up your reputation by using it ‘wrong’.
This is where the conservatism of the finance professional comes into play. Be “old school” and make the best out of the old tools first.
My opinion is current as of today. I will let you know when I believe it is time for CFOs to be active on Google+.
Also, just for the record, I haven’t bothered with Google+ yet. If you aren’t there yet, why should I be?