I find this interesting to dentists for two reasons.
First there are way too many dentists with lame out of date- never been updated- ineffective web sites. What this means is that those out of date sites will be even less visible to Google.
Second, there is no secret sauce that some SEO company has that can guarantee you a top listing on Google. The fact is that for the most part the best way to show up in the “organic” listings from Google is to have a valuable site that people visit often has numerous links and is updated regularly.
The duo defined low-quality sites as those that are a “low-value add for users, copy content from other websites or sites that are just not very useful.
via Google Alters Search Algorithm to Avoid Promoting Low-Quality Sites | News & Opinion | PCMag.com.