David Chalmers has put together a wonderful list of guidelines for respectful philosophical discussion. It’s focussed on in-person discussion, e.g. in seminars. But a lot of it carries over very well to the internet– and, I think, would vastly improve the blogosphere if widely followed. For example…
Don’t present objections as flat dismissals (leave open the possibility that there’s a response).
If you find yourself thinking that the project is worthless, think twice before asking your question.
Object to theses, don’t object to people.
I would add, thinking especially but not exclusively of the internet:
Don’t be dismissive of entire sub disciplines or approaches.
Do not insult people or approaches.
Be mindful of power imbalances, including informal ones.