Srila Prabhupada encouraged all his followers to write. He said that this would be chanting (kirtanam) because it is repeating what one has learned from his books. It is also preaching, because it encourages others to take to Krishna consciousness.
‘And our men, all our men should write. Otherwise how we shall know that he has understood the philosophy? Writing means Sravanam kirtanam. Sravanam means hearing from the authority and again repeat it.’
Srila Prabhupada said that anyone who has heard attentively about Krishna will be able to write. He may not be scholarly but his books will be accepted because they are based on authoritative sources. In contrast, he said, writing by scholarly non-devotees is of no value, but only a jugglery of words.