The Facebook birthday is synonymous with lazy friends. They no longer have to remember your birthday as the service will tell them when they have to post a shallow "Happy Birthday!" on your Timeline. Google+ has lacked the ability to guilt your friends into sending you birthday greetings, but that will all change.
Moritz Tolxdorff, a Google+ volunteer broke the news that users will now be able to post the date of their birth on their public profiles. Of course, like on Facebook, you'll have some control over who can and can not see it. If you want only your close friends to wish you a Happy Birthday and none of your co-workers, you have that option. You probably should just make it public so you can pretend that people actually care. You can also hide it to find out who really cares.
Show your Birthday on your profile!
Google is rolling out a feature to display your date of birth on your profile. As usual you can define who is able to see it.
"When you sign up for Google+, we’ll ask you to provide your birthday so that we can provide you with features like age-appropriate settings when you use Google services and personalized content. If you already have a birthday associated with your Google account, you won't be prompted to enter your birthday. By default, your birthday (day and month only) will be visible to people in your circles. You can always edit who can see it on your profile."
It should be noted that you can't use the traditional Happy Birthday song when wishing your friend a joyful birthday. The company who owns the song, Time Warner, is extremely protective of its copyright and demands thousands whenever somebody wants to use it. Might I suggest these alternatives when sending birthday wishes over Google+ or Facebook.
On second thought, scratch the Birthday songs. You should just hold a rockin' guitar contest with the winner handing over his guitar to the birthday boy/girl.