Personally, I prefer to let such things burn themselves out, and will intervene only if I sense an avalanche beginning, or if one of the taboo topics, like politics, religion or PC vs Mac, is broached. The disadvantage is that it's a lot of work for the admin. If a list grows quickly, the admin may get snowed under. Then the messages will be delayed until the admin breaks out the snow shovels, and the immediacy of the list is lost. Instead of receiving every individual message posted to the list, many people find it more convenient to receive a single message each day which includes the text of all or most of the messages.
Many popular lists give members the option of receiving the digest version.
The drawback is the same as for a moderated list - somebody has to put the digest together. On most discussion lists, you'll see the same questions being asked again and again, which becomes tiresome for the more experienced list participants. You can compile it over time, by picking out the most well-worded answers to frequent questions. Many FAQ lists become valuable resources on their own. The FAQ list can reside on a Web page, or can be retrieved by email, or better yet, both.