Reach is the total audience size of your employee advocates who have authenticated their LinkedIn and/or Twitter accounts through Please Share.
It is determined by adding together the number of followers (Twitter) and connections (LinkedIn) that each one of your employees has within a respective social media network.
For example, if Joe M. has 700 LinkedIn connections and 400 Twitter followers, and Sally G. had 600 LinkedIn connections and 200 Twitter followers, their combined reach is 1,900 people across both LinkedIn and Twitter – or 1,300 on LinkedIn and 600 on Twitter.
It should be noted that reach should always be referenced as the "potential" audience, not the guaranteed audience as it's highly unlikely that everyone in an employee's network will see a particular post.
Within Please Share, reach totals are really designed to indicate that there is when employees distribute content via share requests or reshare/retweet content via engagement requests.
Every time an employee takes shares company content, he or she contributes to the broader distribution of that message.