We just started to hear about this and SEO is not our core (so maybe this is old news - but Google has emailed a few people we know basically telling them their sites are non-responsive or "mobile friendly" and that as a result it would do poorly in search results for searches performed from mobile devices.
What will happen to these old sites? will they be omitted from search? and how long do people have before no one will see them, since a major share of traffic now is mobile?
Did some searching, but didn't find much, hoping someone can point me towards what the "fall out" is, in regards to this Google action - any help would be appreciated!