GoMo is a Google initiative to help businesses to create a mobile-friendly website. The website, helps users find resources to help build their site and gives them information on why mobile-friendly sites are important. They can also test out their existing site, to see how mobile-friendly it is, and let GoMo show them what their site would look like enabled for mobiles. 

Take a look at the video presentation

Why do you need an effective mobile-friendly website?

You can read some very interesting inputs about it in this article from the blog MobileMag.