Know the rules! Most forums and listservs will have a posted set of community rules—take time to read them. You don't want to end up banned from a valuable resource forum for attaching files or images if it's not encouraged. (Most listservs and forums do not encourage file attachments.)
Moderators, as well as fellow community members, can quickly become irritated by constant away messages. If you're taking a vacation, know the policies about automated away messages. Temporarily unsubscribing may be a wiser choice.
If you're new to a particular list, read the archives. This will make you a stronger presence in the discussions. Many listservs, blogs, and online forums have an archive area accessible to members. By quickly (or in detail, if you wish) scanning through topics and comments left by other members, you'll know what has been said and what hasn't. This way you can offer new information to the conversation, not repetitive. If there isn't an archive section you can read through, wait a week or so before joining into conversations.
Keep conversations fresh. Chances are, the topic you want to post to a listserv has been addressed many times before. This is one of the advantages of reading archives. However, private-independent school administrators change seats frequently, so there's always a new personality to add insight to the conversation. If you happen to be the one who's new and you want to post a topic that has been discussed before, be honest with list members. Introduce yourself, tell the community that you're new to your position, and, although you've read through the archives, you're looking for more insight on the particular issue. This will help to keep the conversation fresh and irritability at a minimum.
Don't be that person! Avoid responding to comments with simple agreements. Example: "Me too," "I agree," "Thank you," and/or "Yes." The point of listservs and forums is to share NEW information—not echo everyone else.
Delete past comments from your e-mail reply. When you're replying to a listserv feed, what others have said will be in your e-mail body. Delete these. Send back to the list only what you want to share.
Don't take anything personally. Not everyone will agree on everything. Don't lose your patience if the community veers in a different direction than your beliefs or opinion. Sometimes, it's better to walk away from a conversation, or even the listserv or forum for a while, to regroup. This is far better than saying something you'll regret to colleagues. Remember, these types of mediums are also great ways to network—you never know if the person you're disagreeing with now may be a coworker in the future.
Some great private-independent resources we recommend for staying "in-the-know" this summer:
ISM listservs
IPSEF International & Private Schools Education Forum
Teachers.net