Yet Carey, more than any other musician, established R. & B. and hip-hop as the sound of pop. One of her frothiest and most delightful No. 1 hits was “Dreamlover” (1993), which features a loop of The Emotions’ 1971 soul tune “Blind Alley,” a song made famous by the rapper Big Daddy Kane, who sampled it in his 1988 track “Ain’t No Half-Steppin’. ” Beginning in 1995, rappers started performing guest verses on Carey’s songs. Suddenly, people who would cross the street to avoid listening to hip-hop were bringing rappers into their house, under the cover of Carey. It became standard for R&B stars, like Missy Elliott and Beyoncé, to combine melodies with rapped verses. And young white pop stars—including Britney Spears, ’N Sync, and Christina Aguilera—have spent much of the past ten years making pop music that is unmistakably R&BMariah Carey is awesome, but you can't credit her with either popularizing rap or introducing the 90's pop song rap interlude. Her strength is not in being a pioneer, it's in awesome taste and execution, and excellent career guidance and producer selection (first by Tommy Mottola, now by herself).
--Sasha Frere-Jones in the April 3, 2006 New Yorker
I don't know about the rest of the country, but in the town where I grew up, most pop music listeners "who would cross the street to avoid listening to hip-hop" but who bought Mariah Carey records were already familiar with easy-listening rap from at least three huge singles: Vanilla Ice's "Ice Ice Baby" (1990), Bel Biv DeVoe's "Poison "(1990), and Marky Mark and the Funky Bunch's "Good Vibrations" (1991). (All of the songs I'm mentioning hit #1 on the Billboard singles chart.)
As for mixing melodies with rap interludes, TLC's "Ain't Too Proud to Beg" (1992), Mary J. Blige & Biggie Smalls' remix of "Real Love" (1993), and Salt 'n' Pepa's "Shoop" (1993) predated Mariah's rap conversion by several years. It was obvious at the time--and it still is--that Mariah was trying to follow the direction of pop music, not leading it. What's amazing about her is that she comes up with such great takes on current pop styles.
Sasha also writes that
“The Emancipation of Mimi” includes no songs as effortlessly cheery or as durable as “Dreamlover” and “Fantasy,” partly because Carey’s melodies now meander, in keeping with current trends in R&B, and have lost the clarity that pop demands.
He mentioned Missy and Beyonce in the wrong place earlier. They didn't ape Mariah -- she is drawing on them (and they are drawing on Bone Thugs-n-Harmony, who were the kind of sui generis genre creators Frere-Jones is trying to talk about) for the style of "Mimi", which I would call something like "stop/start rhythm" rather than "meandering".