"I Gotta Feeling" by the Black Eyed Peas is the best selling digital song of all time

"Hip-hop group Black Eyed Peas song I Gotta Feeling is the best-selling digital song of all time, according to Nielsen SoundScan.
The track spent 14 weeks at the top of the US music chart and sold 5.56 million digital downloads.
The song beat Flo Rida's Low, which had previously held the record having sold 5.53 million since March 2008."
Source: Nielsen Soundscan, reported by BBC News, 5th May 2010