We also share aggregated, non-personal data and related usage information, which does not contain any personal information which can identify you or any other individual user, with third parties, including content providers, website operators, advertisers and publishers.
https://getpocket.com/privacy#sharing
From the pocket privacy policy
Read the Pocket and Mozilla FakeSpot privacy policies. They collect a lot if data, including browsing history, and do so via Google Analytics. They then share that data with advertisers.