RSS-Abstract-Words= max[,min]

Sets a default size in words for RSS abstracts, which are available by default.

Documented Restriction: If your server was upgraded from a prior version, RSS abstracts will be available for pre-existing lists only after the LISTSERV maintainer performs a required one-time manual reindexing operation.

RSS-Abstract-Words= has two parameters: a maximum abstract size and a minimum abstract size (both in words). The second parameter is optional, and if left unset, defaults to 50% of the maximum size.  The default (assuming the site-level default has not been changed) is "RSS-Abstract-Words= 100,50".

An abstract is either generated implicitly from the existing text of the message, or may be specified explicitly.

In order to properly specify the explicit abstract, a mail client that supplies a plain-text part that matches the message is REQUIRED. Most, if not all, modern mail clients fit this specification.

In plain text messages, an explicit abstract is specified by using <abstract> and </abstract> tags in the body of the message - typically at the very end, but the explicit abstract may in theory appear anywhere in the message. The closing tag is optional but recommended.

For those using HTML-capable mail clients: If the mail client is unable to provide a user-specified plain-text alternative and instead sends a "canned" message to the effect that mail clients that do not support HTML will not be able to read the message, then the "canned" message will be the abstract. If the mail client is not capable of providing a plain-text alternative message part at all, and provides HTML only, no abstract will be available.

For those posting messages using the web interface: In the message posting interface, you can enable a dedicated text box for entering explicit abstracts. List owners can set the RSSINPUT variable to 1 in the list-specific SKIN template if the LISTSERV maintainer has not made this the sitewide default.

When processing an implicit abstract, LISTSERV stops at the first paragraph boundary after which it has collected at least 'min' words, adding an ellipsis if there is more text (compliant signatures are ignored).

If there is an explicit abstract, the min and max parameters are ignored and the abstract is whatever the user entered. If the stop-on-paragraph-end feature is not desired, simply set "min" to the same value as "max".

If RSS abstracts are not desired, setting the maximum to 0 disables the abstract altogether.

In all cases, RSS-Abstract-Words= may be changed at will, with the change taking effect "from now on." In order to make the new value take effect retroactively, the indexes must be rebuilt manually by the site maintainer.  Because this is a resource-intensive process, it will not happen automatically.