"In a move that has sparked privacy concerns among social media users, Twitter is granting data mining companies access to comb its archives. More than 250 million tweets are sent everyday, representing a treasure trove of personal data. Twitter says it's opening that data vault and selling tweets dating back two years to marketing companies."
Read more: http://www.ctv.ca/CTVNews/SciTech/20120304/twitter-marketing-research-privacy-concerns-120304/#ixzz1ovs66W6Z