When is a good time to have a blog and what do you want to write about. It is a good thing to have one with an Ideal name. As this will attract visitors to your spoken or verbal conversational writing habits. It will allow you to say what you feel from a time that you have a view in any certain topics that you want to cover.
Having a forum with a blog allows your visitors to sign up and to post views themselves.
But you must have a team that will narrate what is allowed and what needs amending by the team that will oversee comments, threads, discussions.