The famous MediaWiki project (of Wikipedia fame) is a very flexible tool, and like all good tools, people find uses for it the original designers didn't intend. Many people use Wikis as their personal pages, or as a quick, cheap substitute for a CMS. At my work, I maintain a knowledge base using it. Often, people refer to the pages for outstanding work and announcements. Often, I find it necessary to show notifications about planned work or systems status during a specific period of time only.
In CMS terms, this is known as an embargo. This extension adds an embargo feature to Mediawiki. It provides an <embargo> tag that shows its contents:
- After a certain date (and, optionally, time), and
- Before another date (and, optionally, time) has passed.
Either of these criteria may be skipped to display content only before a given date, or forever after a given date.
Usage
Remember that ‘embargo’ denotes hiding, not showing. In this context, ‘embargo after’ means ‘don't show after’, and ‘embargo before’ means ‘don't show before’.
To display a seasonal message:
To let people know about an upcoming event until the day of the event:
Displaying a new message after the event:
The date format in attributes before and after follows the rather flexible format of PHP's strtotime() function. In addition dates, you may specify times using the ISO-like YYYY-MM-DD HH:MM format. You may enter US dates in MM-DD-YYYY, but consult the PHP documentation for other options. Don't use relative dates (next Thursday or now + 2 months): these are interpreted with respect to the time the page is shown, not the time it was last edited!
You can use any wikitext whatsoever inside the <embargo>...</embargo> tags.
Installation
Paste the source code into extensions/Embargo/Embargo.php under your MediaWiki installation. Then, load up your LocalSettings.php file and append these two lines:

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