Steven Saus has written a blog post about why you should never rely on social media [ideatrash.net]. In his latest post on the topic he points out that:
If you don’t personally own your website and data, you don’t have a website or data. Quite simply, you cannot rely on someone else for you to have a website, platform, or social media presence.
G+ is used as the example, but the same principles apply to the other social control media.