Why Sudden Change?
Google probably thinks that plus ones are easier to be manipulated as compared to the number of followers. Plus ones although never accepted directly by Google plays some kind of role in the overall ranking algorithm. Google itself says that plus ones are appreciation for things we like on the web. Hence, it clearly means that things that are much appreciated will be given more importance by Google. This has contributed to rising plus one spam. In order to restrict this manipulative behaviour, Google has stopped displaying plus one count on the business pages.
Here are some tutorials that I have written about the hidden power of Google Plus Ones:
Secret Behind the Power of Plus Ones
Plus Ones a Ranking Factor for Google
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