Function strtotime() is defined as below:

int strtotime ( string time [, int now])

But when I try this function, whatever value I provide to 'now' seem no affect to the result at all.
I've tried following example:

echo strtotime("Jan 1 1970"), "\n";
echo strtotime("Jan 1 1970", 10000), "\n";
echo strtotime("Jan 1 1970", time()), "\n";

and the result is(PHP 4.0.6, 4.2.3, 4.3.0, Linux, Windows):

18000
18000
18000

I'm in GMT-0500, so I guess the result is correct.  But what exactly the parameter 'now' for?  I supposed strtotime() function behave correctly,  so 'now' is just meaningless.