GMX plans to show a fake Firefox warning page, screenshot: http://www.browsersicherheit.info/img/anleitungen/ff_win/fir...

  The GMX website is disrupted by a plugin

  (orginal: Die GMX Website wird durch ein Plugin gestört)

As you can see on their "information campaign" page: http://www.browsersicherheit.info/sicherheit_ff.html

They also faked press articles: http://www.browsersicherheit.info/pressestimmen.html (two websites are related to "1&1"-company and they other one is "Bild")