If talking about the advantages of using social networking sites is to share the knowledge of what to do because we can share and comment. Knowledge. Or questions on various matters.
If talking about the advantages of using the social networking site is to exchange information and knowledge on what common interests because we can offer and comments. Exchange of knowledge or questions on the matter.
If we talk about the advantages of using social Networking site is to be able to exchange information and knowledge sharing in the interest because we can offer and provide comments or questions exchange of knowledge on any subject