What is social media?
To me it is any program with a social platform on it which allows me to contact other members by any means. This could be by leaving a message or direct contact.
There are 185 social media sites listed on Wikipedia. Some of these are specialist sites but the majority are for general use. Not all would be of interest to an internet marketer.
The majority of internet marketers join social media to let people know about their products. They are more interested in those areas where they can advertise as well as educate.
Facebook, Twitter, Pinterest, Instagram, LinkedIn and You Tube appear to be the ones that many marketers seem to prefer.