Explain this reasoning to me, and is it common?

[zaphod]

For me it is mostly distracting to have chat turned on. Instead of watching the play when i am not involved in a hand i watch the chat even if the chat is usually just bs.

The most useful thing i can remember seeing in the chat was when somebody openpushed preflop and said oops instantly. Not suprisingly he had AA. He still got a caller though!