...Audible, which was founded in 1995 and introduced an early portable digital audio player in 1997, unveiled several offerings this year. Among them: Customers now can make audio clips to share on social media. They also can give audiobooks to friends through a button that sends an email or a text message with a link to a free download. Audible, which Amazon bought in 2008, saw membership grow 40% in 2015 over the previous year.

Audible increasingly is hiring well-known actors to narrate classics. (One of its top 10 sellers last year was Charles Dickens’s short novel, “The Chimes,” read by Richard Armitage, who played the​ dwarf prince Thorin in Peter Jackson’s film adaptation of “The Hobbit.”)