A safe way of adding a named option/value pair to the options database table of a specific blog. Operationally it switches to the specified blog, runs the WordPress add_option() function, switches back to the previous current blog and updates the cache.
<?php add_blog_option($blog_id, $key, $value); ?>
<?php
add_blog_option( 5, 'myhack_extraction_length', '255' );
?>