With blog-style things now decently supported, there is the problem
that some pages want to be longer than is comfortable for display in a
blog setting. Now wikitext can signal that only the front should be
shown in some contexts, like so:
{{CutShort}}

This is done by the !{{CutShort}} macro. In the future it will take
arguments to specify just when to cut things off.

!{{CutShort}} is not enabled in normal wikitext rendering; it is only
enabled in the new _wikitext:short_ renderer. We assume that things
like the blog entry template will use that one instead of wikitext.

This does raise the interesting issue of how a !{{Restricted}} set
after a !{{CutShort}} works. The current decision is that only
restrictions up to the cut point are checked, because this allows you
to put teasers up for the un-authenticated or wrongly-authenticated
yet hide the full text.

(That this is easier to code and runs faster is only
incidental. Honest. Would ChrisSiebenmann do something like that?)

(No, don't answer that question.)