(salt shaker story)
Mailing lists have their own form of etiquette. You have to be careful to follow the purpose of the list. Posting off-topic questions will quickly earn you a reputation, one you will not soon live down.
Newsgroups have thousands of readers worldwide. Generally there are a few ``gods'' on each newsgroup. For instance, in sci.math.symbolic, you shouldn't argue with Richard Fateman unless you are very, very sure of your point. Richard has been around forever and has seen it all. Every newsgroup has at least one ``god''. For example, Dan Barlow on comp.lang.lisp. Listen; read a lot of entries. It quickly becomes obvious who knows and who doesn't.