One annoying thing that I noticed with Google’s new social networking site Google+ is email and SMS notification. Each time someone mention you in their stream, it will notify you via email and SMS (if you have enabled it). It is a serious issue, especially if you have many people in your Circle, because your email account would be flooded with notifications. Like wise, if you have enabled SMS notifications, then you will be notified on your mobile phone via text messages. Too many SMS is also a big problem. However, you can disable both the Google+ notifications.
Your settings will be saved automatically. Now onwards, you will not get Google+ notifications in your email inbox or mobile phone.
Note: You can always enable the Google+ notifications using the same steps.