Wheep! Wheep! Major performance optimization for index.php: we reduced the
number of SQL on the mainpage with factor 10 and shortened the code with 4
lines.  There is only *one* optimized SQL query left, being:

$result = db_query("SELECT stories.*, COUNT(comments.sid) AS comments FROM
stories LEFT JOIN comments ON stories.sid = comments.sid WHERE
stories.status = 1 AND stories.time <= $date GROUP BY stories.sid ORDER BY
stories.sid DESC LIMIT $number");

 Note: we use a LEFT JOIN to retrieve the number of comments associated
       with each story.  By retrieving this data now, we elimate a *lot*
       of individual queries that would otherwise be required inside the
       while-loop.  If there is no matching record for the right table in
       the ON-part of the LEFT JOIN, a row with all columns set to NULL
       is used for the right table.  This is required, as not every story
       has a counterpart in the comments table (at a given time).