article_snippet: is only currently available to verified users .
article_snippet: (Was prompted about this on opening the app.)'
article_snippet: A Twitter spokesman said the feature is only currently available for these verified users and did not reveal if the feature will be rolled out further.
article_snippet: this appears the filter is opt-in.
article_snippet: When people sign up by email people are also given the option to add a phone number (pictured).
highlights_snippet: Twitter is currently trialling the feature on accounts of verified users only .
  