People are seen as silhouettes as they check mobile devices whilst standing against an illuminated wall bearing Twitter Inc.'s logo in this arranged photograph in London, U.K., on Jan. 5, 2016.
People are seen as silhouettes as they check mobile devices whilst standing against an illuminated wall bearing Twitter Inc.'s logo in this arranged photograph in London, U.K., on Jan. 5, 2016. Chris Ratcliffe Bloomberg
People are seen as silhouettes as they check mobile devices whilst standing against an illuminated wall bearing Twitter Inc.'s logo in this arranged photograph in London, U.K., on Jan. 5, 2016. Chris Ratcliffe Bloomberg