The Community Manager is also called web host communities. Its function is to bring together a community of users around a common interest. It also tries to facilitate trade and ensure compliance with the rules in the community (good behavior).
It develops on behalf of an organization (or brand association) their presence through social media (Facebook, Twitter, Blog ... etc.).
The use of Community Manager has been the growth of the web. Initially, moderators, mostly found on forums and video gaming sites, controlled the smooth functioning of trade between users.
Today their usefulness is not limited to regulate trade. They aim to monitor a community but also to boost the image of the organization. By paying attention, they can detect potential problems and opportunities in the community (reviews, opinions, ideas and suggestions of members) and to maintain a balance.
Indirectly, their desire is to monitor the online reputation of the organization and maintain it through all the social media tools that exist (social marketing).