While Facebook has struggled to make e-commerce a popular activity on its core social networking website, messaging services are increasingly adding transactional capabilities. WeChat, the mobile messaging service owned by China's Tencent Holdings, began letting users book taxis through the service earlier this year. Google's Gmail introduced a feature last year that lets users transfer money to each other.
"I'm looking forward to getting my hands dirty again attempting to build something new and meaningful at scale," Marcus said in a post on his LinkedIn page on Monday. Marcus said that he decided to join Facebook after Chief Executive Officer Mark Zuckerberg "shared a compelling vision about mobile messaging."
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The move comes as PayPal, which has 148 million active users, faces tougher global competition from Amazon.com, which launched a recurring payments program earlier on Monday, as well as Chinese e-commerce giant Alibaba Group Holdings, which is going public later this year.
In a blog post, eBay Chief Executive John Donahoe said Marcus was leaving behind a strong leadership team and PayPal was on track to meet its outlook for 2015.