Finally, Google+ has the ‘Birthday Reminder’ functionality like Facebook. You will be reminded of upcoming birthdays of friends and family in your Circles on Google+. This was by Irene Chung on Google+. Of course this reminder will only be seen if your friends have shared their birthday information with you or they will see your birthday if you have shared this info with the Circle you have placed them in.
As Irene said, “When it’s your special day, we only remind the people you’ve chosen to share your birthday with. Update your Google+ birthday preferences to make sure you’re sharing with the right people: https://plus.google.com/up/birthday. At first you’ll only see birthday reminders if you’re searching in English on Google.com. We’ll be rolling this feature out gradually over the next few days. Here’s to all the happy birthdays to come!”
Google+ allows you to share photos/videos and messages with friends whose birthday it is.Google+ Will Now Remind You About Friends' Birthdays!,