WeChat is a popular messaging app in China that has expanded into other services like payments, games, and businesses. It addresses problems with communication, payments, and separate apps by providing an all-in-one platform. WeChat started as a messaging app in 2011 and has since grown to over 1 billion users, adding features like profiles, games, payments and "mini programs" that allow users to access services from companies within the app. Its business model involves advertising, payments, and official accounts that businesses must verify each year. WeChat has been very successful in China due to its wide range of services and ability to meet many user needs in a single application.