77% of consumers have logged into a web site or app using a social login, according to a new survey conducted on behalf of Gigya Inc., a vendor whose technology lets consumers sign into e-retailer sites using their credentials from such social networks as Twitter, Facebook and Google Plus. That’s a significant jump from two years ago when 45% of shoppers said they had used a social login.

It isn’t just that consumers use social logins occasionally: 66% say that they use a social login “whenever it is an option” or “often.” That is nearly double the percentage with those responses in 2012.

Social login use is growing because it offers a simpler alternative to maintaining separate accounts on every site, says Patrick Salyer, Gigya’s CEO. “Convenience is king,” he says.

That’s particularly true for mobile shoppers because it can be difficult to type in account information on a mobile device’s small screen. That explains why 65% of shoppers say they are “very likely” or “somewhat likely” to rely on social login information when using a mobile device.

When a consumer uses a social login, it enables a retailer to use the data she has shared on social networks to tailor the site to her interests. For example, if a consumer posts on Facebook about her hiking trips a retailer could show her outdoor apparel and gear.

That sort of personalization can be valuable for retailers because consumers push back against marketing that’s irrelevant to them, according to the survey. 43% say they ignore all future communications from the brand after a merchant presents her with irrelevant information or product recommendations, 67% say they unsubscribe from a brand’s e-mail list and 20% say they stop buying from the retailer (participants could select multiple responses). On the opposite end of the spectrum, 20% of respondents say they would be more willing to share information with a brand if it offered more relevant content offers and recommendations.

Market research firm OnePoll conducted the survey of 2,000 consumers between the ages of 18 and 55 for Gigya in July.