For the music industry, the past two decades have truly been the best of times and the worst of times.
After reaching record-setting heights at the turn of the century, with $18.98 CDs selling millions of copies each week, the industry went into free fall, as the Internet made piracy easy and tricking fans into buying substandard albums very, very hard.
Of course, just because the music industry is ailing doesn't mean music itself is in trouble. In recent years, music has wormed its way into nearly every part of pop culture, from TV shows to fundraisers to the viral videos of the Internet.
Here's a look at the biggest events and trends that have shaped the last 20 years in music:
LANDMARK ALBUM Nirvana's 1991 album "Nevermind" -- including the classic suburban-rebel anthem "Smells Like Teen Spirit" -- launched the grunge movement, as well as the envelope-pushing alternative rock platform that continues to flourish on radio today, and inspired countless artists and disenfranchised Generation-Xers by finding success outside the mainstream.
GAME-CHANGING WEBSITE With its launch in 2003, iTunes, the Apple music (and more) Web retailer, changed the way music is distributed, hastening the demise of record stores. It has also changed the way albums are made and marketed, and transformed an album-centric industry into a singles-centric one.
ROCK ICONS The current "Spider-Man" brouhaha aside, U2 has become the template of the Great Rock Band -- balancing crowd-pleasers like 1991's "Achtung Baby" with experimentation. The way 2000's "All That You Can't Leave Behind" became the salve for so many in the wake of the 9/11 terrorist attacks only cements their epic status.
HIP-HOP'S BIGGEST MOGUL Jay-Z really does have "The Blueprint" -- as a hip-hop artist, businessman, author and, now, a website proprietor. His 11 No. 1 albums, the most ever by a solo artist, prove his staying power, while anthems like "Empire State of Mind" (2009) show he is at the top of his game.
TV'S BIG DAWG Starting in 2002, "American Idol" launched the careers of superstars Kelly Clarkson, Carrie Underwood, Daughtry and others, while also bringing the star-making process into America's living rooms and creating millions of armchair music critics, who can discuss "pitchiness" and melisma.
OK, INNOVATOR After a string of stunning albums (starting with 1995's "The Bends") gave them power, Radiohead developed into a prototype of the new millennium artist -- handling its own business, developing new solutions to the industry's issues and still maintaining a high level of artistry.
RAP'S FALLEN HEROES Christopher "The Notorious B.I.G." Wallace and Tupac Shakur. We may never know why 2Pac was murdered in 1996 or why Biggie was killed in 1997. We do know that beefs over money, marketing, rivalries and bragging rights should never grow this unchecked again and that artists this great should respect each other.
HEALING TOUCH When post-9/11 America turned to Bruce Springsteen and the E Street Band for some solace, the Jersey boys delivered "The Rising" in 2002, a mix of wrenching remembrances ("My City of Ruins") and much-needed hope ("Waitin' on a Sunny Day").
RUFFLING FEATHERS When the Dixie Chicks took flight in 1998 with the 12-million-selling "Wide Open Spaces" and the 10-million-selling follow-up "Fly," the Chicks seemed unstoppable. The swiftness and depth of their decline in 2003 after singer Natalie Maines questioned U.S. involvement in Iraq is still stunning, especially after it turned out more questions were warranted.
THE LITTLE ONES Since the arrival of the ex-Mouseketeers in 1999 -- teenagers Britney Spears, Justin Timberlake and Christina Aguilera -- the idea of teens selling to teens hit a new gear. The successes of Taylor Swift (16 when her debut arrived in 2006) and Miley Cyrus (15 for her 2007 debut) have led to Justin Bieber (15 for his 2009 debut) and now 13-year-old Greyson Chance.
THAT THING, THAT THING Lauryn Hill's Grammy-winning 1998 solo debut, "The Miseducation of Lauryn Hill," changed the course of hip-hop, showing that positivity and real emotion had an audience and that women could bring the creativity just like the guys.
GOTTA HAVE FRIENDS Though MySpace has since been surpassed by Facebook, YouTube and Twitter, its 2003 launch enabled musicians to make "friends" with their fans, forging more one-on-one connections and allowing artists to get their message out to fans without a media filter.
HEAR YE, HEAR YE Since Kanye West's 2004 debut, "The College Dropout," he has consistently churned out the most interesting hip-hop around, finding inspiration in prog rock and new wave as well as old-school soul. His successes still outweigh his controversial tantrums, including a stage-crashing dis of Taylor Swift, though the scale could tip at any moment.
PUNK ROCK OPERA Green Day seemed near the end of its punk act, then surprised the world with 2004's "American Idiot." The epic album, which became a Broadway musical and may become a movie, catchily raged against President George W. Bush and the Iraq War, as well as the American culture that allowed them.
THE UNDERDOGS When this year's Grammy for album of the year went to Arcade Fire's "The Suburbs" from the tiny North Carolina independent label, Merge Records, it was practically the final blow to the major-label system. Indie labels now account for more than 30 percent of all sales and are showing growth in a declining industry through niche marketing and small, savvy rosters.
UNIVERSE GONE QUICKLY After Madonna's 1992 album "Erotica" and the accompanying "Sex" book, there were worries that she had gone too far, that she was out of ideas. But 1998's "Ray of Light" was a masterful reinvention, an embrace of the Eurodance style that currently dominates the pop charts. It served as a warning to never underestimate the Material Girl.
ADULT EDUCATION Norah Jones' "Come Away With Me." The surprise, 10-million-selling success of Jones' 2002 debut revealed what had become an underserved market, adult music fans. Since then, record companies have been chasing older-skewing artists, including Susan Boyle, and those with cross-generational appeal, like Adele.
THE REAL SLIM SHADY Eminem, the bestselling artist of the Aughts, sold more than 32 million albums on the strength of his lightning-quick delivery and his lightning-rod attraction for controversy. Accusations of misogyny, homophobia and even racism have always slid right off Slim Shady, now hailed for 2010's "Recovery."
THE KING IS DEAD After his 1991 album "Dangerous," Michael Jackson began to struggle with the law and with prescription drugs until his death in 2009. The outpouring of goodwill after The King of Pop's death made many re-evaluate why they withheld support from him while he was alive.
DASHBOARD CONFESSIONALS Emo-core, the combination of emotional lyrics with hard-core punk and guitar-driven alternative rock known as "emo" for short, grew from twin bases in northern New Jersey and Long Island into an international sensation. The movement swept up several local bands, including Taking Back Sunday and Brand New, and stretched into fashion and the movies.
MUSIC -- THEN AND NOW
1991 Mariah Carey
MUSIC HEARTTHROB'S MOVIE DEBUT
1991 Vanilla Ice in "Cool as Ice"
2011 Justin Bieber in "Never Say Never"
HARD-TO-EXPLAIN NO. 1 SINGLE
1991 "I Adore Mi Amor," Color Me Badd
2011 "Black and Yellow," Wiz Khalifa
UNREQUITED LOVE SONG LYRICS
1991 "I would fight for you / I'd lie for you / Walk the wire for you, yeah, I'd die for you / You know it's true / Everything I do, I do it for you." -- BRYAN ADAMS, "I Do It for You"
2011 "I would go through all this pain / Take a bullet straight through my brain / Yes, I would die for you, baby / But you won't do the same" -- BRUNO MARS, "Grenade"