Since we discussed QNetworkAccessManager, you now have the knowledge you need to integrate Facebook, Twitter, or similar sites into your application. They all use the HTTPS protocol and simple requests in order to retrieve data from them. For Facebook, you have to use the so-called Graph API. It describes which interfaces are available and what options they offer. If you want to search for users who are called Helena, you have to request https://graph.facebook.com/search?q=helena&type=user. Of course, you can do this with QNetworkManager. You will find more information about the possible requests to Facebook at https://developers.facebook.com/docs/graph-api.
If you wish to display tweets in your game, you have to use Twitter's REST or Search API. Assuming that you know the ID of a tweet you would like to display, you can...