i think in social networking. any people have want use internet or app such as facebook line. it's important in marketing have contact or sale. it's have the pros and cons of the social networking. the cons. i thing user is social networking somebody have use social networking a long time. i think to be education low down if use social networking a long time. and use app such as facebook for post about pornography or word bad post in social networking. the pros. it Can exchange knowledge on things of interest