http://www.insidehighered.com/sites/default/server_files/styles/blog_landing/public/technology_and_learning_blog_header.jpg?itok=aQthgJ91By Joshua Kim. As of this writing Twitter has a market capitalization of $24.46 billion dollars. 
To put Twitter into some context, look at Hershey. (Founded in 1894, and on my mind during this Halloween season). 
Hershey is valued at $21.66 billion. Last year Hershey took in $6.94 billion, and recognized $2.86 billion in profits. Read more...