Retailers may have hit record sales over the shopping weekend from Thanksgiving through Cyber Monday, but the impact of social media campaigns many of them invested in is less certain.

Offerpop, which helps retailers including Amazon, Sears and Walmart run social-marketing campaigns, says it saw a 40percent increase in social-media campaigns by its clients for the Black Friday shopping weekend compared with last year.

Yet social media made up less than 1percent of online traffic and sales on Black Friday, according to IBM Smarter Commerce, which tracks sales for 500 of the top retail sites. And that's down from last year. That's based on customers who were referred to a retailer's site through social media and made a purchase right then.

It may not be a bad thing though, given that retailers were using social media more to raise brand awareness than to push sales this year, says Jay Henderson, strategy director for IBM Smarter Commerce.

Target rewarded a number of customers who were tweeting about the company with electronic gift cards over the weekend, spokesman Joe Curry says. It also used an interactive Facebook app to reveal its Black Friday deals by pitting a series of items against each other and asking users to pick which product they thought would go on sale for Black Friday. The game had almost 1 million users in a four-day span, Curry says.

Twitter mentions for retailers also jumped. Mentions of the (AT)DisneyStore handle increased 42percent , the company reports. And tweets with the hashtag (POUND)FairyGodmother, which customers included when they had a question or needed help with a product, were up 40percent from last year.

While it may be hard to track how much this kind of social-media activity benefits retailers in terms of sales, "Most of the retailers we've worked with have all agreed that people talking about their particular store or brand is always going to be better than not," says Erin Robbins O'Brien, head of business intelligence at Viralheat, a data analytics company whose software helps companies track social-media sentiment.

And social media's influence on purchases is stronger than the IBM numbers let on, she says.

"Social media in some way, shape or form is oftentimes one of the first ways someone will hear about something," O'Brien says. "It contributes to not just awareness but actual product decisions."

"Mostly people are using social to discover products and to discover deals," says Mark Cooper, chief marketing officer for Offerpop.