It seems there are at least 16 different artists under the name IO.

1) Io was a emotive hardcore punk band from Pittsburgh, Pa, who released a full length and 7" on Hope Records/Hard Travelin and existed from 2001 to 2003 but played a reunion show in 2005.

2) IO is a mostly instrumental, post-metal, math rock quartet from Birmingham, UK. Website.

3) Two talented music fans and DJ's are behind Ukrainian house music act 'iO': Alex Voznichenko and Artem Zhovtobriukh. Project launched in februari 2009 and since then gained attention from major house music jocks such as Joris Voorn and Bart Skils. (myspace.com/ioukraine)

4) IO is a 4 releases cheap records inhouse project with Erdem Tunakan, Patrick Pulsinger, Gerhard Potuznik and Umberto Gollini.

5) "iO" is the band formed by 3 of the 4 previous Guano Apes members (without singer Sandra Nasic) and singer Charles Simmons. Official homepage.

6) Io was a melodic death metal band from Nurmijärvi, Finland.

7) Io is a black metal band from the United States of America.

8) iO is the drum and bass DJ/producer from Minsk, Belarus.

9) io was an American rock band from North Carolina, relocated to San Francisco, CA, active from 2001-2005. Released the album "Where The Engines Lay" in 2003, Later renamed Dear Kerosene(2005-2006).

10) Io is an artist from Bellingham, WA who makes digital instrumental music and contributes to a pair project with Jon Spinelli called House of Leaves.

11) IO is an Experimental-Industrial/Terror-Noise group from Berlin, Germany.

12) Io is drone/ ambient project of Jonas Laster (see also Father Io)

13) Io is an Austrian busker

14) Io is a experimental-ambient project based in Miami, then Washington, DC, then Toronto, and now in Miami again. Releases on Elegua Records include "Little Haiti Suite," "The Fat Albert Concert," and "Live @ the Ambient PiNG, Vol. 1."

15) IO (Inside Ocean) is a hungarian producer, Mátyás Milkovics's solo production. [url=http://www.facebook.com/pages/IO/140447772669720[/url].

16) Io is an instrumental progressive metal / djent / fusion project by an unknown artist from New York. A 6 song self-titled EP was released on February 27th, 2012 on Bandcamp, currently available for free download.

17) I.O is the name of the artist who made the song Lv.0 or Level 0, which appears in the mobile rhythm games VOEZ and Deemo. Read more on Last.fm. User-contributed text is available under the Creative Commons By-SA License; additional terms may apply.