Content of book appears to be skewed in TV programme

• TV or radio serial
• So a post office for each area is a drama?

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
"melodramatic radio serial" (later extended to television), 1939; so-called because sponsors often were soap manufacturers, from earlier horse opera "a Western" (1927). Shortened form soap for this first attested 1943.

Wikipedia Word definitions in Wikipedia
A soap opera is an ongoing, episodic work of fiction presented in serial format on television, radio, or other mediums. Soap opera may also refer to:

Wiktionary Word definitions in Wiktionary
n. A radio or television serial, typically broadcast in the afternoon or evening, about the lives of melodramatic characters, which are often filled with strong emotions, highly dramatic situations and suspense.