PHP- What is the @ symbol?

[email protected] ("yan") Wed, 4 Sep 2002 03:04:01 -0400

Newsgroups	php.lang
Message-ID	<[email protected]>

What is the @ before a variable? such as @$variable? there is no mention of
this at any site i have visited. please help.
eg the exact context i need help with is in a switch statement. switch
(@$do) ... (statements).

thanks