• According to Duffy, the song is about 'sexual liberty' and 'not doing something somebody else wants you to do'
• Duffy and Steve Booker share writing credits on the song. Steve Booker also produced the track.
• The song was nominated for Best Female Pop Vocal Performance at the Grammy Awards held on February 2009. 'Mercy' did win Song of the Year honors at the 2008 MOJO Awards.
• The single was released on February 25th, 2008, certified platinum in the USA, UK, & Sweden, and topped the charts in many countries while peaking at #27 on the Billboard Hot 100 chart.
• This was the third biggest selling single in the UK for 2008 with over 400,000 units sold.