This strikes me as an excellent explanation of a phenomenon that I’ve seen but haven’t yet been able to label:
Social Proof: The Glue That Holds Social Media Marketing Together:
“When a new prospect encounters your business or marketing for the very first time, there is one factor that will always give you unparalleled influence: social proof. This can come in a variety of different ways like product reviews, client testimonials, video testimonials, videos of you speaking in front of large crowds or on stage, showing how many Facebook fans and Twitter followers you have, etc.”
This is why businesses want to establish social media personas and keep them updated and relevant. A few tweets a day, a few posts a week, and good content of interest to your target market — that, over time, becomes social proof.
Post author Melanie Dodaro offers more explanation, and some details, on that source post at topdogsocialmedia.com.