50% mobile usage http://www.bbc.co.uk/news/technology-14731757 Probably accessibility is a good one to look at. 1 in 10 have a disability so forgetting about making a site accessible is like blocking out 10% of the visitors
Mike R. replied:
Run a report like this to take in http://marketing.grader.com/
Adam P. replied:
http://www.hihinternational.org/
Daniel P. replied:
Message from a great seo chap I know. "Tell your friend re his post on SEO that Google loves great clean content, regularly updates and the power of Google + is where it's at. If you write regular good informative blogs and use the "author rel tags" back to your G+ account you will rank high on Google. There's lots about it on Moz.com but definitely search the author rel tag bit and that will hopefully be a nugget for him. Hope that helps, sorry I couldn't post thus directly"