In a blog post today, Twitter announced that they're "experimenting with new ways of targeting ads," which is their way of saying they're planning to track you around the web—even when you leave Twitter—and relay that information to advertisers to craft better ads. Here's how to opt out.
Twitter Wants to Start Tracking You on the Web, Here's How to Opt-OutIf this sounds familiar, it should. Twitter started experimenting with this kind of off-site tracking a year ago, only then it wasn't explicitly opt-out. Twitter already uses things like Follow buttons and social widgets on websites to see where its logged in users go after they leave Twitter itself, but now they're putting it in print, and that's actually a good thing.
To turn off Twitter's new tracking:
    1. Log in to Twitter and visit your account settings page.
    2. Uncheck the box that says "Tailor Twitter based on my recent website visits."
    3. Uncheck the box that says "Tailor ads based on information shared by ad partners."
    4. Scroll down and click "Save Changes."
    If you have Do Not Track enabled in your web browser, you'll see the checkbox like mine above that indicates it's enabled and neither of the boxes should be checked.