How vital is it for a site to have a mobile site for mobile SEO?

[yvonneq]

With the exponential growth in mobile device sales and usage and an expected 980% growth in advertising next year for/on mobile devices, we at http://www.mobilewebsitegurus.com decided that it was time to help companies create great looking mobile websites that are user friendly and SEO friendly at affordable rates with tons of features built in from the start. However, when selling our design, how important is it to have a GOOD mobile site compared to a big one to rank on mobile devices? We head that Google was thinking of only showing mobile sites on mobile devices. NOT TRUE. Then we read/heard that the rankings were MUCH BETTER if you had a mobile site, but after a lot of research we found that too NOT to be true. On most sites there were NO difference. So what is the TRUTH about this and is it maybe just that it will happen, just has not happened yet - the different rankings for mobile and regular sites on mobile devices that is? ANY insight in this would be great not only for us but for the entire SEO community Thanks. ALSO, add "Mobile SEO" to the boxes below of "Topics" since mobile SEO will grow in importance.

[DanielFreedman]

I'm not sure I understand the question, but along the way  the original poster seems to be  suggesting that a mobile strategy should always and everywhere be a high priority for every business. I'm not sure I agree with that premise.

I recently optimized for mobile the site of a client who mobile traffic has doubled to 25% in the last few months. Much of the site traffic is from 18-35 year old males who are affluent and educated...and access the site daily for updated content.  So it was kind of a no-brainer. We just rolled the mobile optimization into an overall site re-design. There is only one site.

But another client is business-to-business. Users access the site only from work, during business hours, from Monday to Friday. It's a very tech un-saavy user basis, with over 65% on IE. Mobile traffic is so small it's hard to measure. The site is not optimized for mobile. We just did a site upgrade, without optimizing for mobile. I recommended we wait another year.

That said, when building new sites from scratch these days, I would always optimize for mobile.

As to the question of whether you should build a mobi version of a legacy site, my answer would mirror the one above: follow Google's recommendation and just have one site.

I'm trying to think of a situation where it would make sense to launch a mobile version of a legacy site with identical content....but I can't think of one.

[irvingw]

If this is a legitimate question, proper tagging and display, quick page speed times for mobile and user engagement such as bounce rate etc will be factors in helping Google to decide to give one site better mobile rankings over another. Google is recommending one site for both web and mobile. So simply the fact that one site is purely mobile and another is both mobile and web does not mean that the mobile only site should automatically rank better because it's a .mobi or whatever.