Well, some of this can be based on the year end charts although billboard monitors from February-March
Top Artist Justin Bieber Maroon 5 One Direction
Rihanna
Taylor Swift
Top Hot100 Song
Some Nights Somebody That I Used To Know Call Me Maybe
One More Night
Payphone
Top Billboard 200 Albums 21
Babel Red
Up All Night
Take Me Home
Top Duo/Group
Coldplay One Direction
Fun.
Maroon 5
Mumford & Sons
Top New Artist
Carly Rae Jepsen
Gotye
PSY One Direction
The Lumineers
Top Touring Artist
Lady GaGa
Coldplay Madonna
Roger Waters
Bruce Springsteen
Top Male Artist Justin Bieber
Bruno Mars
Drake
Flo Rida
Jason Aldean
Top Female Artist Nicki Minaj
Rihanna
ADELE Taylor Swift
Carly Rae Jepsen
Top Hot100 Artist Maroon 5
Taylor Swift
Rihanna
Fun.
Flo Rida
Top Billboard200 Albums
Justin Bieber
One Direction Taylor Swift
ADELE
Mumford & Sons
Top Digital Songs Artist Carly Rae Jepsen
Taylor Swift
Flo Rida
Fun. Maroon 5
Top Radio Songs Artist
Nicki Minaj Rihanna
Maroon 5
Fun.
Flo Rida
Top Social Artist
One Direction Rihanna
Katy Perry
Taylor Swift Justin Bieber
Top Streaming Artist PSY
Rihanna
Nicki Minaj
Baauer
Drake
Top Pop Artist
One Direction
Bruno Mars Maroon 5
ADELE
Justin Bieber
Top R&B Artist
Ne-Yo Rihanna
Chris Brown
Alicia Keys
Usher
Top Rap Artist Drake
Nicki Minaj
Pitbull
Flo Rida
PSY
Top Pop Album ADELE - 21
Maroon 5 - Overexposed One Direction - Take Me Home
One Direction - Up All Night
Justin Bieber - Believe
Top R&B Album Rihanna - Unapologetic
Usher - Looking 4 Myself
Chris Brown - Fortune
Alicia Keys - Girl On Fire
Frank Ocean - Challell Orange
Top Rap Album
Nicki Minaj - Pink Friday:Roman Reloaded
Macklemore & Ryan Lewis - The Heist
Rick Ross - God Forgives, I Don't
2 Chainz - Based On A T.R.U. Story
Kendrick Lamar - Good Kid, M.A.A.D. City
Top Digital Song
Fun. feat. Janelle Monae - We Are Young Gotye feat. Kimbra - Somebody That I Used to Know
Carly Rae Jepsen - Call Me Maybe
Macklemore & Ryan Lewis feat. Wanz - Thrift Shop
Maroon 5 feat. Wiz Khalifa - Payphone
Top Radio Song Gotye feat. Kimbra - Somebody That I Used to Know
Carly Rae Jepsen - Call Me Maybe Maroon 5 - One More Night
Maroon 5 feat. Wiz Khalifa - Payphone Bruno Mars - Locked Out of Heaven
Top Streaming Song (Audio)
Fun. - Some Nights
Fun. feat. Janelle Monae - We Are Young Gotye feat. Kimbra - Somebody That I Used to Know
Ellie Goulding - Lights Carly Rae Jepsen - Call Me Maybe
Top Streaming Song (Video)
Fun. feat. Janelle Monae - We Are Young
Carly Rae Jepsen - Call Me Maybe Macklemore & Ryan Lewis feat. Wanz - Thrift Shop
PSY - Gangnam Style
Taylor Swift - We Are Never Ever Getting Back Together
Top Pop Song
Ellie Goulding - Lights Carly Rae Jepsen - Call Me Maybe
Maroon 5 - One More Night
Maroon 5 feat. Wiz Khalifa - Payphone
Bruno Mars - Locked Out of Heaven
Top R&B Song
Alicia Keys feat. Nicki Minaj - Girl On Fire Miguel - Adorn
Frank Ocean - Thinkin Bout You Rihanna - Diamonds
Trey Songz - Heart Attack
Top Rap Song
Flo Rida feat. Sia - Wild Ones
Flo Rida - Whistle
Kanye West, Big Sean, Pusha T, 2 Chainz - Mercy Macklemore & Ryan Lewis feat. Wanz - Thrift Shop
PSY - Gangnam Style
Top Dance Song
Baauer - Harlem Shake David Guetta feat. Sia - Titanium
Nicki Minaj - Starships
PSY - Gangnam Style
Rihanna - Where Have You Been
Top EDM Song
Baauer - Harlem Shake David Guetta feat. Sia - Titanium
Calvin Harris - Feel So Close
Calvin Harris feat. Florence Welch - Sweet Nothing
Swedish House Mafia feat. John Martin - Don't You Worry Child
Great noms!! Rihanna, Maroon 5, 1D & Taylor!!
However i think that all noms are so 2012!!! i was expecting more from the releases during the last months of 2012 like P!Nk, Unapologetic era, Justin Timberlake, More Bruno mars