Constant Contact, an email marketing company, announced its acquisition of mobile app developer CardStar this week. CardStar developed a mobile app where consumers are able to store all of their existing loyalty cards, rather than having to carry multiple, physical cards. Constant Contact will continue to operate CardStar’s free mobile loyalty application, which is available on major mobile platforms, including iPhone, Android and BlackBerry. Retailers can also offer coupons and special deals through the app. Terms of the deal are undisclosed.

Constant Contact’s acquisition is part of its makeover into an all-purpose marketing platform for SMBs. At the end of last year, Constant Contact launched a new offering, Social Campaigns, aimed at helping SMBs grow their fan base and drive engagement on Facebook, Twitter and LinkedIn. Mark Schmulen, general manager of social media at Constant Contact, is scheduled to speak at ILM East in March about local social media, customer engagement and the direct connection to sales.

CardStar’s employees will join the Constant Contact team, including CEO and Founder Andy Miller and CTO and Founder Danny Espinoza. Miller will serve as the director of mobile products. Espinoza will join Miller’s team to lead future product direction.