If you have a Google Plus Brand Page (as opposed to Google Plus Local) you need to add links pointing back to your website, blog, or social media channels. This is easily done and the links section of the Google Plus Brandpage is shown in the screen shot below.
If you have a Google plus Local page (the map feature) then disregard the image below. If on the other hand you’re launching a website or blog which does not have a physical location but will require a Google Plus Brand page, bear this in mind. Interlinking your social networks in the following way is beneficial for referral traffic and perhaps there is SEO benefit to be had too.