Surveys and homework assignments are usually ignored and labels you as a Newbie. Requests that information be emailed because you don't normally read the group is considered rude. Avoid stories about kids with tumors that want postcards, and the story about Neiman Marcus cookies, and the one about the modem tax. And no longer valid. Check the FAQ's, ma'am.
Chain letters are illegal.
Be careful of crossposting. Post your article to only to appropriate groups. If you must go on a tirade or flame someone, try to limit yourself to email. Assume that people are speaking for themselves, not their organization. Even if they are posting from work.