In 2002, Joost was a founding board member of DGTF (the German Society for Design Theory and Research), which she has also chaired since 2008.

During the winter semester 2007/2008 Joost was a visiting professor at the University of Applied Sciences in Hildesheim (HAWK) for Gender & Design.

Within the scope of the Generation 50+ project, she participated in the development of the DECT telephone Sinus A 201 (funded by Deutsche Telekom) and received the iF product design award in 2010.

In the negotiations to form a Grand Coalition of Chancellor Angela Merkel's Christian Democrats (CDU together with the Bavarian CSU) and the SPD following the 2013 German elections, she was part of the SPD delegation in the working group on digital policy, led by Dorothee Bär and Brigitte Zypries.

In 2013,[4] questioned Joost's independence in research and teaching on the basis of its close ties with Deutsche Telekom, citing, among others, objections by Pirate Party politician Ralf Engelhardt and lawyer Jörg Heidrich.