PayPal, part of eBay Inc, did not disclose a purchase price.
PayPal is a dominant online payments service with more than 120 million users, but its growth has slowed in recent years and the company's new president, David Marcus, is looking for ways to revive that.
Iron Pearl, a Silicon Valley start-up, analyzes data and develops computer models designed to drive the viral spread of products and services over the Internet, often across social networks such as Facebook Inc.
This niche in the technology world is often called growth hacking, and PayPal's Marcus said on Thursday that Chudnovsky and Currier are among the leading growth hackers. Other top growth hackers include Chamath Palihapitiya, who helped drive Facebook's own rapid expansion, Marcus noted.
"It's time for PayPal to take this very seriously," Marcus said. "This is a key function of any growth company."
Technology companies such as Facebook, LinkedIn Corp and Twitter have specific groups of employees who focus on growth hacking and PayPal should too, he added.
Chudnovsky will take on the new role of vice president of growth at PayPal and report directly to Marcus, while Currier will be a "growth adviser" to the company, Marcus said.
Chudnovsky and Currier started Tickle, an early social media 7company that used online viral marketing and was acquired for $100 million by Monster in 2004.
Chudnovsky also helped design online growth strategies for start-ups such as GoodReads, Path and BranchOut.
GoodReads, a social network for readers to recommend books to friends online, was acquired by Amazon.com Inc, the world's largest Internet retailer, earlier this year.
© Thomson Reuters 2013