http://mycroft.mozdev.org/deepdocs/browsertag.html#c23 Could you email me the one that didn't work and the one that did at mycroft.mozdev.org AT googlemail.com and I'll see if I can work out the problem... Mozilla/5.0 (Windows; U; Windows NT 5.1; en-GB; rv:1.8.0.1) Gecko/20060111 Firefox/1.5.0.1