We all understand that if you include personal information or post using a known alias, a little bit of searching may identify you. If your IP address is made public in the post or email, it can be used to narrow down who or where you are. Even simply correlating known data, that is linked to your identity, with previously anonymous data can sometimes identify you. And the popular easy to regurgitate advice is that "nothing" you do is anonymous.
The fact is, if you're careful and there isn't enough of a motivation to go to the level necessary to identify you, you can participate anonymously in many discussions.
It's also possible to maintain the option of anonymous discussion in the future if people realize where it has value and make an effort not to give their privacy away voluntarily.