[kayyay]

Any discussion board where the majority of users has a specific background or shared interest is likely to converge in their opinion on some issues, the echo chamber is simply built in.

You're free not to participate in a discussion you've come across ten times though.

[izacus]

This is amplified with the fact that any voting based discussion board allows a group of users to silence opposing opinions and drive away people that hold them. As a result, you get a self-perpetuating amplification cycle where the loudest silence everyone else.