Social Networking Sites

My impression of Twitter and Facebook are a little similar. Both sites enables users to create posts, upload pictures, comment/like posts and pictures. However, Instagram and LinkedIn are very different than Twitter and Facebook, although both sites are social media sites yet they operate differently. For example, Instagram doesn't allow users to upload statuses and posts, Instagram enables users to upload photos and comment/like the photos. LinkedIn on the other hand operate very differently, the social media site is more of a professional network where users are able to connect with other LinkedIn users. Since the site is business orientated, is it also utilized as a job portal where users look for jobs through connecting with other users.