Mobile Redirect Website vs Responsive Design
Question: Do dedicated mobile sites, i.e. “m.(your domain here)” hurt a company’s search power by having separate domains?
First off, for marketing purposes having a mobile site, be it a responsive design or an “m.” redirect is better than having a site that is not mobile friendly. However, the “m.” though good, is the least SEO-friendly way to implement a mobile website. There are several factors that stack against the “m.” mobile site:
1) Google will see the “m.” as a separate website. When people link to your website, some will link to “m.” and some to the core website. What this does is dilutes your pagerank (weight of your inbound links). A responsive site receives 100% of all inbound links, whereas the “m.” technique will spread it out between two site.
2) Google can judge that the “m.” content is duplicate and may discredit it via the Panda update and other ranking algorithm penalties.
3) Maintenance is much more difficult, as content must be updated independently from “m.” and the desktop website versions.
4) Not all browsers and devices honor the redirection from the desktop site to the “m.” site.
5) The look and feel between desktop and mobile devices is the same for responsive sites. However the look may change when being redirected to the “m.” site, which can confuse or upset a site visitor.
6) When the “m.” site is design, this “m.” subdomain will have no inbound link history or pagerank. It will inherit some pagerank from the desktop site through the redirect, but it will have none of its own inbound links. A responsive design is the same website regardless of being visited via desktop or a mobile device, so all inbound links give full credit to both desktop and mobile site renditions.
Additional supporting info: https://moz.com/learn/seo/mobile-optimization