Who was seen goofing off on their phones during the requested moment of silence for Mike Mike in Ferguson?  Who else?

Those would be the Kardashians:  Kim, Paris, and Dopey (I'm not sure of their names).

According to Pulse Networks post-op on the Emmys: 

Kim Kardashian and her sisters, Kendall and Kylie, caused some outrage on social media on Sunday night (August 24th) during MTV's Video Music Awards. The siblings were caught on camera texting while rapper Common was asking the audience to take a moment of silence for the conflict happening in Ferguson, Missouri.

Common asked the crowd for everyone's attention and said, "I want us all to take a moment of silence for Michael Brown and for peace in this country and in the world." The cameras then turned to Kim, Kendall, and Kylie who were seen chatting and looking at their phones. People took to Twitter to call the girls "selfish", "self-absorbed", and "disrespectful" for their actions.