No, we’re not talking about us. The gaudy 500 billion social media impressions is the sum total calculated by Forrester Research as it sought the answer to: just what impact do our favorite social media sites, forums and networks have on the products and brands in our lives? In other words, what impression, if any, can we make on our peers by talking about a particular product or service?

According to Forrester, the influence of a blog post or Tweet or YouTube upload is wide-reaching. Here’s what they have to say:

Word-of-mouth social media endorsements rival in effectiveness that of digital advertising. Forrester writes:

For comparison, for a 12-month period ending September 30 last year, Nielsen Online estimates advertisers created 1.974 trillion online advertising impressions, compared to the 500 billion impressions people make on each other about products and services. So people’s online impressions on each other about products and services are about one fourth of the online advertising impression. And peer impressions are more credible than advertising, since they come from friends. Take those number into your next budget meeting!