If somebody sends you something, it's very easy to send it on to more people, or to store it in a public place. On the other hand, if you reveal someone else's secret, there is almost always a written record showing that you are the one who did it, so it is easier to find out who leaked a secret. Community A community is a group of people who talk to one another because they share common interests. In years past, it was difficult to form communities unless people lived near one another. Indeed, the tradition of the 'letters to the editor' column in a newspaper, which are very widely read, is a recognition that there is value in letting many people speak.
Communities linked by online communication can be geographically diffuse and more specialized.
And communities can form around nonverbal activities such as computer games or chess. The communication of ideas requires language, especially when the correspondents disagree with one another. If the unity of the group comes from, say, liking Nintendo games, it is not necessary to use language to say 'I like Nintendo'. But if the unity of the group comes from a shared interest in the Book of Revelation, it is hard to express that interest without language. Perhaps someday automatic language translation will have become sophisticated enough to permit a community to form without a common language.