One thing I like in Everything2 that's not in PerlMonks is the "Re:" box on top of each writeup. People often use it to tell you they like what you write (or they don't) but it's very practical so it's widely used - it's just a shortcut for a message from you starting with "Re: node -...".

It helps knowing new people and making friends and connections. Of course, such a feature is not mandatary - you can use it indipendently from the down-up vote gadget - it's just a help for the lazy guys like me.

By the way, in my experience during these weeks, it seems the private /msg feature is less used on PerlMonks than on Everything, but I don't want to over-generalize. What do you think about that?