Express, Now (and perhaps more similar libraries) are wonderful pieces of software, both programmer- and user-friendly.
However, they all have the same drawback: they rely on socket.io.
I still (after 15 months) believe that socket.io leaks memory.
There are forum rumours that memory leakage really occurs, but deeper in some lower-level libraries.
Whatever leaks - cannot be used for production servers.
So, hersserver does the same with a long-poll mechanism, completely removing socket.io usage.