After a decade long hiatus Cluster reunited in April, 2007. They performed at the opening of documenta 12, a major exhibition of modern and contemporary art held every five years in Kassel, Germany on June 15, 2007. In late 2007 Cluster performed at concerts across Europe and played the United States in 2008 for the first time since 1996. Cluster disbanded at the end of 2010.
Cluster's musical style has varied greatly over the years, ranging from Experimental Music on early albums, to rhythmic Krautrock or Progressive rock on Zuckerzeit and After the Heat, to new age or ambient music on many tracks in the middle to late '70s, to truly avant-garde or industrial on Live in Vienna. Cluster always has an avant-garde edge even on gentle, ambient pieces. Michael Waynick, who reviewed Cluster & Eno for AllMusic writes a description that applies to more than the one album: "...too emotionally rich to waste as mere background music, evoking feelings of hesitancy and regret that rescue the music from mere vapid prettiness."
The diversity of styles on the various Cluster albums, with significant changes in musical direction from one release to the next, makes it difficult to categorize Cluster's music. The factors which are present on all 13 albums include the use of electronic instrumentation, loops, and the use of unexpected sounds to create a sense of experimentation.
Cluster has been widely influential not only to ambient and electronic music artists, but to techno, electronica and popular music as well. Artists and groups whose music has been influenced by Cluster include David Bowie, Robert Rich, John Foxx (formerly of Ultravox), Alex Paterson of The Orb, Coil, Oval, To Rococo Rot, and Mouse on Mars.
Dieter Moebius, Hans-Joachim Roedelius and Conrad Schnitzler formed Kluster in 1969 after the three had met at the Zodiak Free Arts Lab. This trio released three albums, Klopfzeichen, Zwei-Osterei and Eruption. When Schnitzler left the group, Roedelius and Moebius became Cluster. They were joined by Conny Plank on their debut self-titled release in 1971. They continued as a duo thereafter but worked extensively with producer/engineer Plank until his death in 1987.