During that time, he was also a co-curator of the 1st MOMENTUM biennale [no] in Moss, Norway, in 1998, with Lars Bang Larsen [sv] and Atle Gerhardsen.

[4] From 2006 to 2008, he was co-curator of Uncertain States of America with Hans Ulrich Obrist and Gunnar B. Kvaran at CCS Bard College, the Serpentine Gallery, the 2nd Moscow Biennale, the Rudolfinum Galerie, and the Astrup Fearnley Museum, among other locations.

[14] In 2018, Birnbaum announced that he would leave his post to head up Acute Art, a company with an interest in creating virtual-reality and augmented-reality works in collaboration with artists.

He has written on artists Olafur Eliasson, Pierre Huyghe, Dominique Gonzalez-Foerster, Wolfgang Tillmans, Cerith Wyn Evans and Paul Chan.

He has produced academic texts and translations on Novalis, Edmund Husserl, Martin Heidegger, Gottlob Frege, Ludwig Wittgenstein, Jacques Derrida, Thomas Bernhard, and Jean-François Lyotard: