This story is sensationalist and false. There is no external advertising network that Facebook wants to sell your data to. Facebook is changing this particular policy so that they can share data among its subsidiaries, like Facebook Ireland and Instagram. The "tracked changes" version of their data use policy [1] makes this clear on the last page (emphasis mine):

> We may share information we receive with businesses that are legally part of the same group of companies that Facebook is part of, or that become part of that group (often these companies are called affiliates). Likewise, our affiliates may share information with us as well. We and our affiliates may use shared information to help provide, understand, and improve our services and their own services.

[1]: https://fbcdn-dragon-a.akamaihd.net/cfs-ak-ash3/676592/128/4... (PDF)