On the internet there are different appreciations groups for different aims and reasons. In the recent past also the field of architecture is becoming part of that phenomena e.g. on Facebook. There are two groups which are offering a platform for sharing and discussion about the Postmodern and Brutalist Architecture history.
For example there is the the group “Brutalism Appreciation Society” which now has at least well over 5,000 members and recently the POMO, the “Postmodernism Appreciation Society“, which was founded by Oliver Elser from the German Architecture Museum in Frankfurt am Main. Members of these groups post photos of architecture, show the postmodern buildings of the 70s to the 90s.
Further information about the two groups: