"Kala" featured live instrumentation and layers of traditional dance and folk styles such as soca and the urumee drum of gaana, rave music and bootleg soundtracks of Tamil film music, incorporating new styles into her avant-garde electronic dance music. The songs, artwork and fashion of "Kala" have been characterised as simultaneously celebratory and infused with raw, "darker, outsider" themes, such as immigration politics, personal relationships and war. In February 2007, the first track from the album to be made available to the public was "Bird Flu", which was posted with an accompanying music video to her MySpace. Later that year, M.I.A. featured in the song "Come Around", a bonus track on Timbaland's 2007 album "Shock Value" and a track on "Kala". The album's first official single "Boyz" was released in June 2007, accompanied by a music video co-directed by Jay Will and M.I.A., becoming M.I.A.'s first top ten charting song. The single "Jimmy", written about an invitation to tour genocide-affected regions in Rwanda that the singer received from a journalist while staying in Liberia, was released next. The single "Paper Planes", described a "satire on immigrant stereotypes", and the EP "Paper Planes – Homeland Security Remixes EP" were released digitally in February 2008, the single eventually selling three times platinum in the US and Canada, certified Gold in New Zealand, and becoming the 29th most downloaded song in the digital era in the US and earning a Grammy nomination for Record of the Year. "Paper Planes" is to date XL Recordings' second best selling single, and by November 2011 it had sold 3.6 million copies in the US, currently the seventh best-selling song by a British artist in the digital era. In 2007, M.I.A. also released the "How Many Votes Fix Mix EP" which included a remix of "Boyz" featuring Jay-Z.