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 Tuesday, Jan. 5, 2016. Twitter Inc. may be preparing to raise its character limit for tweets to the thousands from the current 140, a person with knowledge of the matter said. Photographer: Chris Ratcliffe/Bloomberg via Getty Images

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 Tuesday, Jan. 5, 2016. Twitter Inc. may be preparing to raise its character limit for tweets to the thousands from the current 140, a person with knowledge of the matter said. Photographer: Chris Ratcliffe/Bloomberg via Getty Images