Chart star Lady GaGa was the year's biggest artist for online listening, according to a leading music site Last.fm.
Tracks from her album 'The Fame' were played more than 18.5 million times by the site's 35 million-strong community.
The singer - known for her wacky outfits - had her songs played six million times more than her nearest rivals The Killers.
The company analysed the tracks from full-length albums which had been streamed by visitors on the site to come up with their top 10.
Lily Allen is the highest placed British artist in the list, figuring at number three with second album 'It's Not Me It's You', with Prodigy at four.
Brit acts dominate a separate list of the artists who are deemed to the hottest of 2009 and who have made a sudden impact on the site with south London's The XX topping the chart.
Around 35 million people use the site to stream music for free.
Most played artists of 2009 and albums:
1. Lady GaGa - 'The Fame'
2. The Killers - 'Day & Age'
3. Lily Allen - 'It's Not Me, It's You'
4. Prodigy - 'Invaders Must Die'
5. Franz Ferdinand - 'Tonight'
6. Beyonce - 'I am ... Sasha Fierce'
7. Animal Collective - 'Merriweather Post Pavilion'
8. Green Day - '21st Century Breakdown'
9. Yeah Yeah Yeahs - 'It's Blitz!'
10. Kanye West - '808s & Heartbreaks'