Nowadays a monke or monkey is what an Anonymous hacker group member is called. It is term originated from the vigilante called N, to defame and dehumanize the group members for "their lack of normal human intelligence and behaviour".
*N: Attack of the monkeys is happening again. Well not for long! ð
If you recieve the letter N in any form in the criminal underwold means (especially in hacking) it means you're marked by the vigilante called N and you'll be killed if you get in prison.
*Anon: Let's hack this idiot again!
*SMS: N