1) Now i teach some topic like internation politic and education situation in the country. It is very important becouse some politics  circumstances force us travel a lot and  change study places.
2) A lot of information i check in the education platform, this for example https://truowl.com/. Social networks help too, LinkedIn for example
3) Unfortunately my son is 5-years old and he can't imagine how is it works.

Social networks for learning languages are a good practices and i also provide this approach. In addition you can get more information here http://www.elidublin.com/the-7-best-social-networks-to-learn-languages/. Special for me the best is Busuu. It has about 50 million registered users from more than 200 countries and it has features that are very similar to Facebook, such as friend requests, groups and chats.