I have 2 variants on my homepage : "Free Trial" http://www.zookshop.com/?comb=1-b http://www.zookshop.com/?comb=1-b "Sign up : 30-day Free Trial" http://www.z

I have 2 variants on my homepage : "Free Trial" http://www.zookshop.com/?comb=1-b http://www.zookshop.com/?comb=1-b "Sign up : 30-day Free Trial" http://www.zookshop.com/?comb=2-b http://www.zookshop.com/?comb=2-b The first one is way more effective than the other. I have no data with "a month" because I haven't tested it, but it seems to be common knowledge that "30 days" is better, because it looks longer.