I use the lastest version of WP Super Cache and enabled Gzip compression. You can see the site running at http://www.stadtklatsch.com.
Today I checked my site at http://gtmetrix.com/reports/www.stadtklatsch.com/yUFjtK4N and it tells me to enable gzip compression. Is gzip compression not running, although I enabled it? Is there another way to check this?