This page is a simple explanation of mailing lists run by Rootsweb for those who are inexperienced with them (Newbies).
An electronic 'mailing list' is a collection of people with an interest in a particular subject, where an email sent to the mailing list address is resent to all the people on the list.
Many lists are set up to cover a multitude of subjects, and in genealogy, most are based upon a surname or a region, although a few also exist that cover subjects like periods of history, emigration, etc.
Mailing lists are a safe way of talking to other people. Viruses cannot be transmitted by the email itself, only as part of an attachment to the email. Rootsweb does not allow attachments to be posted to the list, thus protecting the subscribers.
The addresses of people subscribed to a list are not available publicly, which means that being a member will not make you more susceptible to spamming. The only time your email address is visible to others is when you post to the list, and even then it is only visible to the other subscribers.
To join a mailing list, the person needs to 'subscribe' to the list with a valid email address. Subscription is free, and is merely a tool that the computer uses to know who to re-send the emails to. The subscription process is automatic and requires that the person send an email to a particular address (see later for further details). If successful, an acknowledgement/welcome message is sent back to you, giving your more details. To unsubscribe from a list is just as easy.
Once you are subscribed to a list, every time another subscriber 'posts' to the list (sends an email to the list address), you, and all other subscribers, will get a copy of that post. Likewise your posts are sent to all the subscribers. You may also reply to a post, by replying to the list, so that others will see your reply, or you may elect to respond privately to the author of the post.
There are two ways in which you may receive your emails from the mailing list, List mode and Digest mode.
In List mode, every post to the list, is re-sent to you almost immediately as an individual email. If subscribed to a very busy list you may receive up to 50 emails in a day, and on a quiet list, maybe a couple every now and then.
In Digest mode, the posts are saved up and sent to the subscriber as a single combined post once a day. If the list has a very busy day you may get more than one digest a day. No posts are missed out, you just get one bigger email rather than lots of smaller ones.
A subscriber may subscribe in either the List mode or the Digest mode. It is a matter of personal preference. For newbies, I would suggest they subscribe in Digest mode, but if you are an active researcher, then the List mode would be a better selection.