Campbell Mithun has found a new hiring tool: Twitter. And 13 well-crafted “tweets” will help a group of applicants land a summer internship.

The Minneapolis ad agency is set to select its 2011 summer interns based on a series of 140-character tweets. Potential candidates who have just completed their junior or senior year in college are invited to apply for the “Lucky 13” internship.

Here's how it works:

Interested applicants register here.

They then submit 13 “career-launching tweets” that must contain hashtags that designate their application and the area in which they seek an internship. (Applications are being accepted for internships in the following fields: account management, media, creative, and technology.)

The tweets must also demonstrate the applicant's qualifications for the internship they seek.

Tweets sent between February 13th and February 15th will be considered for the openings.

The firm says that the distinct hiring process gives intern candidates an opportunity “to showcase their strengths and their social-media moxie.”

Kristine Olson, director of corporate communications, said in a Tuesday phone interview that the company has been monitoring its corporate Twitter account “super aggressively” as conversations have sprung up regarding the internship. She said that 66 people registered for the program within 36 hours of announcing the application process-and there are now more than 100 registered applicants, many of whom are “showing a certain mastery and adeptness of this way of communicating.”

“Submitting an application via Twitter supports the digital and creative nature of our business,” Debbie Fischer, vice president and human resources manager, said in a statement. “We anticipate a lively and interesting social-media exchange.”

The agency will select finalists based on the submitted tweets. Those finalists will be invited to an in-person interview, and final selections will by announced by the end of March. The paid internships run for 10 weeks: June 6 through August 12.

Campbell Mithun's creative hiring method has garnered national attention-including an article in Advertising Age.

Olson said that the 13-tweet application process originated from an internal team looking for a new way to set up the summer internship. The company regularly uses Twitter to monitor industry news and make announcements. It has even used Twitter to carry on real-time conversations while live-streaming a video panel discussion, but Olson said that the Lucky 13 program is the first time that the company has used Twitter in an application process.

Campbell Mithun is Minnesota's largest advertising agency based on its annual net revenue, which totals an estimated $53 million.