text: Trending topics are sometimes the result of concerted efforts and manipulations by fans of certain celebrities or cultural phenomena, particularly musicians like Lady Gaga, Justin Bieber, Rihanna and One Direction, and novel series Twilight and Harry Potter. Twitter has altered the trend algorithm in the past to prevent manipulation of this type with limited success. Twitter also censors trending hashtags that are claimed to be abusive or offensive. Twitter censored the #thatsafrican and #thingsdarkiessay hashtags after users complained that they found the hashtags offensive.
  Lists
  In late 2009, the "Twitter Lists" feature was added, making it possible for users to follow a curated list of accounts all at once, rather than following individual users. Currently, lists can be set to either public or private. Public lists may be recommended to users via the general Lists interface and appear in search results. If a users follows a public list, it will appear in the "View Lists" section of their profile, so that other users may quickly find it and follow it as well. Private lists can only be followed if the creator shares a specific link to their list. Lists add a separate tab to the Twitter interface with the title of the list, such as "News" or "Economics".