A longer summary linked in the article: <a href="http://krebsonsecurity.com/2013/08/buying-battles-in-the-war-on-twitter-spam/" rel="nofollow">http://krebsonsecurity.com/2013/08/buying-battles-in-the-war...</a><p>The original paper: <a href="http://krebsonsecurity.com/wp-content/uploads/2013/08/USENIXtwitteraccountpaper.pdf" rel="nofollow">http://krebsonsecurity.com/wp-content/uploads/2013/08/USENIX...</a>