Google Optimizer helps you to improve conversion rate of your website through A/b testing & Multivariant testing.. A/b Testing - in A/b Testing there would be 2 different design lay outs for website and in that there would be giving compression of conversion rate through 2 different design lay outs. Multivariant testing - in Multivariant testing there is likely to be up & down of content is one single page. testing effectiveness of this content changing on conversion rate. thts called multivariant testing.