Pop superstar Lady Gaga was named top artist of the year by Billlboard on Thursday after taking home the top new artist a year ago.  Billboard bases its year-end chart on artists' performance on its Billboard 200 albums and Hot 100 singles charts throughout the year.  Taylor Swift, who won the Top Artist award in 2009, finished in second behind Gaga.  Ke$ha took the honors in the Top New Artist category, and her hit single, "Tik Tok," sit's atop Billboard's Hot 100 year-end singles chart.  Check out this clip of Gaga when she was just plain old Stefani Germanotta belting out a cover of Led Zeppelin's "D'yer Mak'er"