The real reason why Twitter is copying Facebook and wants to know your birthday

Twitter wants you to celebrate your birthday on its social network, and it will even give you some animated balloons for your profile when it's your special day of the year.

But, that's not the only birthday present Twitter will give you.

Buried beneath those birthday balloons is the real reason Twitter wants to know your birthday: it wants to better target ads.

In a link to a help center article on profile visibility, Twitter acknowledges that your birthday information will be used to "customize your Twitter experience."

"For example, we will use your birthday to show you more relevant content, including ads," the site reads.

That's valuable information to Twitter because, just last week, the social site announced new ad targeting capabilities based on Twitter personas.

These 'personas' include categories like millennials, adults 18-54, seniors, Gen Xers and baby boomers - all subsets that might be easier to distinguish if Twitter had someone's birthday on hand.

Facebook has been asking for your birthday and your real name since you signed up. While the company's "authentic name" policy has spawned protests against the company in the past year, it's been a key linchpin in the site's ad strategy.

Twitter, on the other hand, doesn't make anyone use their real names or register with their birthday. If you're an advertiser, that makes it tougher to reach the right consumers for particular products - for example products intended for people that are at least 18 years old.

That doesn't mean Twitter has been entirely shooting in the dark.

When I looked at my Twitter ad insights, I found out that my followers happen to be millionaires with a higher-than-average affection for deli dips. Now that Twitter is celebrating its users' birthdays, it's hoping that it will be able to tell me a little bit more.