Twitter said today that it would begin showing individually targeted ads using cookies, an effective online tracking technology that has also fueled concerns about Internet privacy.
Twitter will further allow retailers to attach anonymous versions of their customers' email addresses, known as hashes, to its advertising engine to individually target the customer base.
The privately owned company, valued at close to $10 billion by investors, has ramped up its advertising capabilities ahead of a widely expected initial public offering next year.
Twitter's new feature, which is expected to raise its advertising rates and revenues, arrives amid heightened public debate over the erosion of privacy online.
In recent years both the European Union and the Federal Trade Commission have probed the extent of tracking technologies used by sites such as Facebook. Last year, European authorities began requiring websites to inform visitors that cookies were being placed on their computers.
It also said it would give users the option of disabling cookies with a "do not track" option in their browser. Many leading browsers such as Mozilla Firefox and Internet Explorer contain such options. Twitter users can also wholly opt out of ads tailored by outside data by opening their account settings, the company said.
The efforts by authorities, particularly in Europe, to clamp down on tracking technologies have spurred a furious backlash from the media and technology industries, which argue that cookies are critical to the whole $100 billion Web-advertising market.