Which one is the best way to communicate? Is it Local/own/mother language or is it the globally accepted language like English that may influence better and in more effective way to communicate with the global people.
If the meaning for social media is to create some influence on the network, then it must be global language for an effective communication. Otherwise, it may hamper the viral effect after a certain point of time.
If updates are available in say French, then to us, the people who are used to English, it is difficult to grasp the exact wave. Participation stops.
Moreover, if local language say Bengali is expressed in written English, then also the process create a lot of difficulties for the end users across the friends network.
Now come to the marketing or Optimization. What happens?
Expressions with native languages would entail a local buzz. Hence a Niche Product. The way to globalize the fact would be a simple translation in English of the chats.