I don't respond on this list to posts which are not signed.
Generally I have chosen this policy so that:
1) I can prioritise spending my time on paying customers. There are people on the list who enjoy talking and being a part of the list, but don't actually play Middle-earth PBM, or pay another license to play. Such people are welcome on the list, but shouldn't expect the same kind of service as I give players. I've only got so much time in the day and I want to spend my time as best I can.
2) I find that if someone doesn't sign their name that they have a tendency to use more aggressive language. Email is a bad enough medium for transmitting ideas and add to that the difference between cultures (we have players from all over the world) and you have recipe for misunderstandings and potential disasters.
3) I can respond to the player's query with speed and more appropriately. For example if I get an email from Ulrik Bisgaard saying that he hasn't got his turn I can dutifully ignore it...
(Only joking Ulrik, I'll do it "tomorrow"...).
I sometimes get email exchanges like this:
Player: "Clint, My turn hasn't turned up!!!!"
Clint: "which turn?"
Player: "my game 123 turn,"
Clint:"who are you?"

4) It's much more pleasant chatting to someone you know and are able to share bits that you have in common. Having met quite a few of you I find that relations between GM and player are much improved when writing back and fore and hence more fun for everyone.
5) I try to contact anonymous players off list sometimes but I generally put that as a lower priority than dealing with named players.
6) We will no longer have any Nuaght Nurses offering us risque benefits. Whilst these mails might seem like a bit of fun, they'll get worse with time and given that some of our players are under 18, its responsible to keep the mailing list clean.
As I deal with a lot of emails anything that you guys can do to help me speeds up the process of getting a reply out to you - ie you get better service.
Hope this helps gives you an insight into my devious mind. 
Clint