Just another test for the Google Plus API.
https://soundcloud.com/ghostek/shackleton-you-bring-me-down

It appears that G+ embeds a live player for soundcloud in the post, but none of this turns up in activities.list. This issue is logged inĀ https://code.google.com/p/google-plus-platform/issues/detail?id=407 but there's been no progress.