I have found you need about 200 conversions and to let the experiments run for a 2 months to get rid of the novelty effect (regardless if a winner has been foun

I have found you need about 200 conversions and to let the experiments run for a 2 months to get rid of the novelty effect (regardless if a winner has been found). A conversion must also be a real sale, by that, I mean people make the mistake of using visits or free signups, and the landing page is optimized for clicks and free accounts not revenue. A perfect example of a failure here is Adwords.com. The Adwords landing page is designed to get people to signup for an account, rather than to generate revenue. 99% of adwords signups lead to dead accounts, because google does a bad job of setting customer expectations on the marketing site.