Not too hard for reddit, hard enough for the average user. This means that for the purposes of having a conversation with someone else, you're basically anonymous. It's the same level of anonymity that web forums had back in the day before all user-created content started ending up on Facebook and it's progeny.

Right but I think their picture will be disjointed and incomplete. Something like 99% of all users are lurkers who never post a single comment.

I think GP meant anonymous to other users - not Reddit itself.