I usually browse the recent posts page when I'm not logged in. If I do see a topic I'd like to participate in, I then log in but then I'm presented with a different page and I've no idea what area the topic I want is. So I give up.
Also I'm not sure what the posts about newly published scientific journals do? There isn't any discussion after the announcement. Access to the journals often requires a subscription. Researchers already know how to search databases.
In my case, I work at a large research university so I can gain access but many cant.