Revisions to the alcohol industry’s marketing code now requires brands to check ages before engaging fans on social media. This has made advertising on Twitter quite challenging for alcohol companies, which up until April 2011, were banned from buying ads on the platform all together.

Now, big brands such as Coors Light, are working with Twitter to create an age-checking tool that will allow alcohol companies to verify their followers’ ages and target the over-21 audience.

Unlike Facebook, which requires all members to enter their date of birth upon sign-up, Twitter doesn’t have an age requirement, making it difficult to verify the age of its users.

To remedy this, the company has partnered with Buddy Media to utilize Direct Messages (DM) to create an age-verification process. Here’s how it works: When a fan follows a brand, he or she is sent a DM with a link to a site that asks for date of birth.

That individual has 24 hours to fill out the form to be able to follow the brand. Age verification is a one-time process, so once approved, fans will be able to follow additional alcohol brands right away.

This isn’t necessarily a surefire method. According to a Twitter spokesperson, the company is trusting fans to enter their valid birthdate as it has no plans to cross reference it with third-party data.

Currently Twitter is testing this program with a small group of advertisers, including MillerCoors and Heineken. These companies are now able to purchase Promoted Tweets and to be featured in Twitter’s “Who to follow” section. If successful, the program will roll out to a larger group.

[Via: AdAge, Image credit: Ed Kohler]