Had I posted this, I would have lost all my points! Anyway, here is the explaination:

my = declare a variable.
$data = variable name.
() = similar to shift or pop.
@_ = an array that you populate and send it off to a sub routine or a function.

Example

$var = 'some sort of data';
&My_Sub($var);

sub My_Sub
{
  my($data) = @_;
 Print $data . "\n";
}

output:

some sort of data
[download]

Blackadder