Apart from the implementation of a proprietary virtual token and the subsequent financial ecosystem, the integration of blockchain with the popular social media platform should bring improved security features like encrypted messages and data or better user account identification. This could take more than a few years, and Facebook is not even interested in an ICO.
https://www.notebookcheck.net/Facebook-is-experimenting-with-blockchain-tech-may-launch-its-own-cryptocurrency.303362.0.html
why would anyone need this other then buying drugs online or supporting ISIS?