At the end of the "42nd Street" number, Billy and Peggy pull down a curtain or shade with the word "Asbestos" written on it. This can be a confusing reference to 21st-century viewers, who may only be familiar with asbestos as a mineral composite which is now known to cause the lung cancer mesothelioma, but during the first part of the 20th century asbestos was an often-used flame-retardant component in building materials. It also would have been a reference familiar to theater people, since live-performance theaters were at the time required to have a curtain made of asbestos that would separate the stage from the audience in the event of an on-stage fire. In that context, the presence of the curtain in the film is the movie's way of implying that whatever Billy and Peggy are going to do behind the curtain, it will surely be "hot."
In one of the opening scenes, Bebe Daniels is reading the February 20, 1932 issue of The New Yorker magazine, with its trademark top-hatted Manhattanite on the cover. This is not the premiere issue (2/21/1925), as previously thought. The New Yorker runs the premiere cover once every year on the date closest to the date of the first issue in 1925. A close comparison of the covers from the 1932 and 1933 anniversary covers (available at the New Yorker web site) shows this to be the one from 1932.
In the finale, dancers on stage pass a store named Reticker's. It was named after Warner Bros. art director Hugh Reticker, who labored at the studio for two decades but did not get screen recognition until two years after this film was made. It's likely he had a hand in designing this set also.
Both Harry Warren and Al Dubin are credited onscreen for both music and lyrics, but no songs are credited onscreen. However, Warren wrote the music for all the songs recognized and listed in the soundtrack, and Dubin the lyrics for those songs which were sung.
One of the lines in the song "Shuffle off to Buffalo" is "when she knows as much as we know/she'll be on her way to Reno/while he still has dough." Contemporary audiences would have recognized this as a reference to the fairly common practice of moving to Reno, Nevada, for a short-term stay to obtain a divorce. At the time of the movie's release (and for at least 25 years afterward), Nevada had some of the most lenient divorce laws in the country, especially compared to New York, where there were few accepted grounds for divorce and the standards of proof for those grounds were so high as to be almost impossible (for instance, evidence of adultery had to be in the form of eyewitness testimony or photographic records of the act); and even then, divorces took a year to be final. By contrast, Nevada granted a divorce for almost any reason after only a six-week-residency period.
The groom (Clarence Nordstrom), in the "Shuffle Off To Buffalo" sequence sings to the bride (Ruby Keeler): "I'll go home and get my panties, you'll go home and get your scanties". In the early 1930s, in the US and Europe, the word for the undergarment "panties" was synonymous with "undies" and applied to both men and women.
This film, released on March 9, 1933, single-handedly rescued the movie musical, which had been considered a money-losing proposition since mid-1930. Early "all talking, all dancing" musicals typically suffered from severe camera restrictions coupled with poor musical staging, and soured the public on the genre in general (Universal's huge losses from the lively King of Jazz (1930) had put an unofficial moratorium on the musical) and no other studio wanted to risk producing one. Warners, at the time of the film's release, had Gold Diggers of 1933 (1933) nearing completion and pre-production plans were well underway for Footlight Parade (1933), all utilizing the talents of Busby Berkeley. The success of this film would convince Radio Pictures to produce Flying Down to Rio (1933) (released that December). Other major studios would continue to shy away from musicals throughout 1933, although Paramount would proceed with plans to produce the lavish Murder at the Vanities (1934) toward the end of the year.
The original Broadway production based on this film opened at the Winter Garden Theater on August 25, 1980, ran for 3486 performances, won the 1981 Tony Award for the Best Musical and was nominated for Best Book for a Musical.