PHP 5 supports static class functions, which is a compiler hint that enforces static usage.

Without Static
<?php
class Foo {
    function 
getName() {
        return 
$this->name;
    }
}

print 
Foo::getName();
?>
Output
With Static
<?php
class Bar {
    static function 
getName() {
        return 
$this->name;
    }
}

print 
Bar::getName();
?>
Output