When visitors to Univision.com "Login Con Facebook," they agree to let the Spanish-language media giant access their public profile data, birthdate, friend list, email address, current city and likes. Portland, Ore.-headquartered Janrain helps Univision and other clients manage those logins and analyze the data to better understand who is coming to their websites. Now, Janrain is adding to that data by acquiring tiny startup Arktan, whose technology enables online comments and reviews and offers services such as analysis of historical Facebook data.

The two firms have worked together for "several years," according to Larry Drebes, CEO and chief technology officer of Janrain. By acquiring Arktan, Janrain will now package data products and services from both firms, including Arktan's comments, review and poll data. While Arktan can analyze actual content of social posts enabled by its platforms, Mr. Drebes said simply knowing that someone left a comment or responded to a poll is valuable for clients.

"Really what we're talking about here is activity that gives you a way to know that they are very interested in your website or product," he said.

Dr Pepper Snapple Group has used Janrain as its centralized identity management system for all its digital properties, and has worked with the company since 2011. "Through this system, we're able to not only understand user preferences in how they interact with our brands, but also learn from and adapt to user behavior and interests in a low-friction manner," said Pat Lawley, manager-marketing technology at Dr Pepper Snapple Group. He said he expects the acquisition to bring "increased efficiencies from working with a centralized partner when building and deploying such solutions."

The Arktan buy also brings social TV technology to Janrain. Arktan partnered with Facebook in India to operate on-air and digital graphics fueled by data from Facebook Keyword Insights API during the 2014 Indian Premier League cricket event.

Janrain helps clients including Pfizer, Universal Music Group, Whole Foods and Samsung capture information about site visitors that it can then use to target ads by location, age, gender and interests. The company can also create look-alike models using first-party profile data, extending the reach of client audiences by finding additional people with similar attributes.

Social logins like the "Sign in with Facebook" and "Sign in with Twitter" buttons have become ubiquitous, not only because they make site registration quick and easy for users, but because site publishers can glean a lot of information about their audiences through them.

For instance, Janrain client Universal Music Group can tap into data showing which bands those who log into its site like on Facebook or follow on Twitter. That information can be used to pinpoint which of the music label's own artists have similar characteristics, then Universal can recommend them on its site or via emails.

Janrain has 160 people on staff, according to Mr. Drebes, who said there are around five people employed by Arktan. He added that he does not expect any executive changes at Arktan. Both firms are privately held; terms of the deal were not disclosed.