For the first time, Twitter will allow advertisers to target users based on things they did off the service, like web browsing, as well as personal information like an email address.
The company announced today that it is opening up to third-party data, which will allow advertisers to target people who've visited a website or provided data as part of a purchase. In a move that seems aimed at differentiating itself from competitors, Twitter will allow users to opt out of targeting that uses third-party data altogether by unchecking a box in their account settings.
In contrast, Facebook doesn't let users opt out of retargeted ads served through its exchange or ads served through its "custom audiences" product that uses emails and other data points like phone numbers and addresses to match users. Similar to custom audiences, Twitter will use a process called "hashing" so that emails used to enable the anonymous match are provided in a scrambled, unreadable form.