The changes could allow a company, such as a fashion retailer, to advertise a sale to those Twitter users with a store’s loyalty card.
Advertisers will be able to create "tailored audiences" lists from email addresses in their own customer relationship management (CRM) database or a database from an ad partner.
Retailers will be invited to share "unreadable scrambles" of its card members’ email addresses with Twitter, which the social network will then match to the relevant Twitter accounts.
The social network will also allow advertisers to create tailored audiences using Twitter usernames or user IDs, to identify key influencers and target them with a promoted account, encouraging them to follow the brand.
CRM and Twitter IDs will also be available to advertisers for "exclusion targeting", to target users who do not have a loyalty card.
Users will be able to opt out of the service by unchecking a box in their privacy settings, next to the "tailor ads based on information shared by ads partners" message.