Wikipedia:Wikibreak

A wikibreak, wikiholiday, wikivacation, or leave of wiki-absence is when a user/member of Wikipedia takes a break from Wikipedia. This means they will not make changes to articles on Wikipedia, and they will not read new messages you send them. The break is over when the user returns to wiki. This can be after a few days, weeks or months.

There are some reasons why users take a break:

The user can put up a sign on her/his userpage to let you know they are on a Wikibreak.
If you want to take a Wikibreak, you can put this text on your userpage: {{wikibreak}}. This will automatically put a template on your page.
The template will look like this, but with your username as the first word:

Wikibreak is taking a short wikibreak and will be back on Wikipedia soon.

Also, you can make a template appear with your own writing. Just type {{wikibreak|message=(your message here)}}, and it will look like:

(your message here)