We're seeing a new sense of frustration, in Blogger Help Forum: Something Is Broken . How do I prevent the constant offer to Mention people in your posts with Google+? in Post Editor? This is a new Blogger / Google+ feature. Like many Google+ features, this one can be refused. Many blog owners, seeing this offer, refuse it - and are never bothered by it, again. Their refusal is retained, by Blogger, in a Blogger cookie. If you refuse the offer properly, Blogger Post Editor will remember your refusal, and not bother you again - if your browser / computer does not unwisely block cookies and scripts.
What Blogger won't tell you