What it is: Social search is like standard search in that it is used to gather information. But where algorithmic search engines such as Google use mathematically based equations to determine a site's relevance, social search engines draw their information from online communities.
People search for information by posing questions in order to receive responses from fellow users, and these responses are then posted on the sites.
Who's doing it: Sainsbury's has linked with Yahoo! Answers in the Food and Drink section. It asks questions and invites users to answer. Holiday firm Thomson is also partnering with Yahoo! Answers in its travel section.
US presidential hopeful Hillary Clinton recently used Yahoo! Answers to ask for views on healthcare in America. She received 33,000 responses in just over 24 hours.
The lowdown: Social search is seen as another development in user-driven content online, giving marketers an opportunity to engage with consumers.
"It's a direct marketing environment because it connects directly with an audience," says Stephen Taylor, regional vice-president at Yahoo! Europe. "You can find where to do something, what the information is, and communicate with people who have actually done it."
George Nimeh, digital managing director at agency iris, believes companies may start building their own search engines to promote brands, or continue partnering with existing ones.
"There's value for the direct marketer in the vertical spaces," says Nimeh. He believes social search can be exploited in niche sectors. "These highly targeted environments are a great thing in direct marketing," he says.
But Duncan Parfitt, account director at Steak Media, thinks it is too early for direct marketers to capitalise on the medium. "Social search is like an online version of PR," he says.