The death of Adam Yauch, known to rap fans as MCA, a co-founder of the Beastie Boys, shocked music fans, including the group’s peers in the entertainment world (not to mention the political and media communities.)
MTV: Run DMC remember Adam Yauch
TheGrio: Remembering Adam Yauch, Beastie Boys’ best rap songs
Here’s a taste of what the famous have been tweeting at the hashtag #MCA.