The problem with groups was it was used by 0.5% of users, and most of the playback was actually fake spam plays. The soundcloud spammers had all the gaming figured out on that part of the system and it was basically worthless.

I know, because I worked on getting it shutdown. Not because I disliked the idea myself, but with no developers working on fixing it, the feature needed to be removed in order to cleanup the database spam and a huge chunk of a legacy code base.

We wanted to replace it, but nobody could convince management to fund it with headcount. But that's the story of SoundCloud, fantastic levels of miss-management.