I just noticed the Site Performance Panel! It suggested to install FireBug add-on + Page Speed add-on! Now the add-ons suggest to use gzip compression, to Leverage browser caching! I found a plugin for WP called WP-Super-Cache that does the compressing, and some code for the .htaccess to Leverage browser caching. Would that have any impact on the site! I did not notice any difference, except that the add-on does not show warnings anymore!