Forums are also known as community software, newsgroups, bulletin boards, threaded discussions, and many mailing list archives provide threading of emails.
CMS Review runs a Forum for the CMS community at CMS Forum.
We hope to have separate web pages with an integrated Forum for each of the major CMS programs.
Many web users do not distinguish between forums, community software, newsgroups, bulletin boards, threaded discussions, and mailing lists (list-servs).
Simple list-servs broadcast an email to a (generally anonymous) list of subscribers. If the sender does not include a return email address, the message is anonymous. For this reason, we think of standard list-servs not as communities, but as "anonymities."
A community keeps track of its members. You are required to join to access any forums or mailing lists. Registration is usually free, as they derive their income from advertising on the site. Communities may offer space on the community server for members to have their own personal web pages. They may gather information about members in a database, which then can be searched to locate specific members.
Forums and discussion groups use a web interface. They show "threaded" discussions (emails with responses to that email). They include email addresses for all participants, so you can contact other members of the forum. And they send nothing to your email address (unless you elect such an option). You visit them to see what is happening. The largest provider of forum web sites is eGroups.com, now owned by Yahoo. Some sites publish the number of subscribers. Because of the "network effect," sites with the largest number of members are generally the most valuable.
Newsgroups are part of the original Usenet, with recognizable domain names, like sci.lang.translation. They are available via the nntp news protocol (the news server setting in your browser), or through web-based interfaces like deja.com, acquired by Google. Newsgroups may be completely open or moderated. Unmoderated groups are notorious for postings which may be completely off-topic (OT) and add a lot of noise to these important information channels.
Mailing lists are joined by sending an email to the list server from the email account that wants to receive posts to the list. Sometimes a standard instruction must appear in the body of the message - to subscribe, to unsubscribe, or perhaps to subscribe to a once-per-day "digest" of the email messages. A digest reduces the number of emails from dozens or even hundreds per day to a single email with brief summaries (usually the subject line) of each email message.
List-servs will send you a required confirmation of the request to join (so that strangers can not join in your name). This confirmation contains detailed instructions on unsubscribing, getting the digest if available, etc. It may also point you to a web site associated with the list. There you can expect to find access to an archive of the lists past messages. If the archive is searchable, you will be able to locate mesages on specific topics or that contain keywords. The list may also offer a FAQ (Frequently Asked Questions) with tips on how to use the mailing list and its archive.