<Li> LivingSocial: an online marketplace that allows clients to buy and share things to do in their city . </Li> <Li> Lockerz: an international social commerce website based in Seattle, Washington . </Li> <Li> OpenSky: is a registered trademark of Harris Corporation and is the trade name for a wireless communication system, invented by M / A-COM Inc., that is now a division of Harris RF Communications . </Li> <Li> Pinterest: a web and mobile application company that offers a visual discovery, collection, sharing, and storage tool . </Li>

Which of the following social commerce features allows