Blogs were one of the earliest forms of social networking where people were writing 1,000 words. When we moved to status updates on Facebook, our posts became shorter. Then micro-blogs like Twitter came along and shortened our updates to 140 characters. Now we are even skipping words altogether and moving towards more visual communication with social-sharing sites like Pinterest.
Dr. William J. Ward, Social Media professor at Syracuse University, from The Rise Of Visual Social Media
Taking a photo is so much easier than writing 1000 words. Less friction = more sharing