This is possible:
"everybody can start one message thread (and comment others)"
BUT
Is it possible that before writing own message, others messages would be invisible? And after posting message of his own, others threads become visibile also. (I havent found that option yet.)
-> Minimum influence by others before "making mind of one`s own"
-> Curiosity
-> Shared knowledge "as a price"
-> Different angles to subject -> bases for critical argumentation