????評分高居iTunes和流媒體音樂網站Spotify前列的饒舌歌曲中有一個詞反復出現，它不是什么時尚俚語，也非改頭換面的咒罵之詞；這個詞就是“助陣”。Billboard的20大藍調即饒舌單曲排行榜中，有10首歌至少有一位助陣歌手，有2首歌甚至邀請了不止一位助陣歌手，很多都是邀請的像德雷克、克里斯?布朗、蕾哈娜、揚?杰子和泰賈等赫赫有名的歌手。“現在全球最火的歌手是助陣歌手。每張唱片都少不了這家伙，”饒舌歌手Dr. Dre的律師彼得?帕特諾開玩笑說。

????饒舌音樂歷來依賴合作、采樣和重新混音。但如今，助陣歌手已從饒舌藝術的特征之一，變成了其商業成功的核心內容。“饒舌歌手越來越像企業家。他們意識到，邀請其他歌手助陣新歌是實現自我突破的一種重要手段，”華納唱片（Warner Music）的聯席首席執行官托德?莫斯克維茨表示。他曾任Def Jam Records的總經理。“不光是為電臺制作的單曲，所有歌曲都是如此。歌手們共同錄制一張唱片時，他們就互相贏得了對方的粉絲。”莫斯克維茨

????案例一：坎耶?韋斯特2010年11月發布的專輯《我的奇特幻想》（My Beautiful Dark Twisted Fantasy），助陣歌手多達22位，包括尼基?米娜、史威茲?畢茲以及嘻哈樂隊Wu-Tang Clan的成員RZA和拉克沃恩。Bon Iver樂隊、Pusha T和瑞克?羅斯甚至參與了多首歌曲。有一首歌曲《所有的光芒》（All of the Lights），演唱歌手包括約翰?傳奇、The-Dream、托尼?威廉姆斯、賴恩?萊斯利、查理?威爾森、艾利?杰克遜、艾麗西亞?凱斯、菲姬、卡迪小子、蕾哈娜和埃爾頓?約翰。專輯正式發布前幾周，韋斯特每周都在網上發布一首新的單曲，稱為G.O.O.D. Friday （以其唱片公司命名）系列。每首歌都有助陣歌手，如賈斯汀?比伯和魯普?費阿斯科等。

????隨著這股趨勢而變化的是經濟因素。歌手們不再因為僅僅出現在一張專輯中就獲得報酬。莫斯克維茨稱：“這就像是投桃報李，藝術家A作為助陣歌手在藝術家B的專輯中唱了一首歌后，藝術家B也會同樣出現在藝術家A的專輯中。”好處是曝光率，可能贏得新粉絲，以及演唱會和商業合同等。如果獲得報酬，酬勞往往是固定收費，大牌明星是每首歌10萬美元。另外，預付未來版稅也很常見。

????很多協議——特別是不涉及財務往來的協議——都是一時興起。制作人兼饒舌歌手賴恩?萊斯利表示，紐約大型的錄音棚所剩無幾，歌手們總是能不期而遇。他說：“有一次我正在為神奇小子錄音，凱利?希爾森正巧在旁邊一間屋錄音，因此就有了一首單曲。”G.O.O.D. Friday系列歌曲Christian Dior Denim Flow的來歷也是一樣。萊斯利解釋稱：“那是一個晚上，我進錄音棚，看到好多熟悉的面孔。老天，約翰?傳奇，卡迪小子，勞埃德?本克斯，賴恩都在……我們得搞出點什么名堂。我走過去把按鍵和節奏設好，班克斯和卡迪小子即興發揮。都是非常開放的合作氛圍。”他說，一切自然而然，“我不用擔心結果如何”。

????One word appears repeatedly among the top-rated rap songs on iTunes and Spotify. It is not a piece of in-vogue argot or even a masked expletive; it's the word "featuring." Of the top 20 singles on Billboard's R&B/Hip-Hop chart, 10 have at least one guest vocalist. Two feature more than one guest, many of them with familiar names like Drake, Chris Brown, Rihanna, Young Jeezy and Tyga. "The biggest artist in the world right now is Featuring. That guy is on every record," jokes Peter Paterno, Dr. Dre's attorney.

????Hip-hop and rap have long relied on collaboration, sampling and remixing. But the guest appearance has gone from simply a part of the artistic fabric of rap to a core feature of its commercial success. "Rap artists have become more entrepreneurial as a necessity, and they've realized a big part of them breaking is to get others on their songs," says Warner Music (TWX) co-CEO Todd Moscowitz, previously general manager at Def Jam Records. "It's not just about singles for radio, it's about ubiquity. They gain fans from each artist they do a record with."

????Exhibit A: Kanye West's album My Beautiful Dark Twisted Fantasy, which was released in November 2010. It contained an astounding 22 guest vocalists including Nicki Minaj, Swizz Beatz, as well as Wu-Tang Clan members RZA and Raekwon. Bon Iver, Pusha T, and Rick Ross each appear on multiple tracks. One song, "All of the Lights," has vocals from John Legend, The-Dream, Tony Williams, Ryan Leslie, Charlie Wilson, Elly Jackson, Alicia Keys, Fergie, Kid Cudi, Rihanna and Elton John. And in the weeks leading up to the album's official release, West posted a new single every week online, calling them G.O.O.D. Friday tracks after his label. Each featured guest vocalists such as Justin Bieber and Lupe Fiasco.

????The economics have shifted along with the trend. Artists no longer necessarily get paid simply for appearing on a major release. "It's almost always just a trade now, where one artist will do a verse on someone's album for a guest verse on their own record," says Moscowitz. The prize is exposure, plus gains reaped down the line from new fans and opportunities like concerts or merchandising deals. When they are paid, compensation is often a flat fee, with bigger stars pulling as much as $100,000 per track. Advances against future royalties or copyright credits are also common.

????Many agreements -- especially ones that have no financial component -- are made on a whim. Ryan Leslie, a producer and R&B singer, says there are so few big studios left in New York that artists will often find themselves in close proximity. "There's a studio video of me making a record for Fabolous, and Keri Hilson just happened to be in an adjacent room recording, so it turned into a single," he says. The same thing happened with the G.O.O.D. Friday song "Christian Dior Denim Flow." Leslie explains, "It just happened that the night I came by to see 'Ye, everybody was in the studio. He looked around and said, 'Man, we've got John Legend, Kid Cudi, Lloyd Banks, Ryan... We gotta do something.' I went over to the keys, the beat got laid, Banks and Cudi did their verses. It was a very open and collaborative vibe." When that happens, he adds, "I don't worry about the back end."