Reach shows the potential number of people that might have come across the news found. How this is calculated varies on the media type. Following is an explanation of how we establish the reach for each media type.
Articles: Based on Alexa Reach*. Potential reach.
Blogs: Based on a combination of Alexa Reach and Twingly's Blog tank. Potantial reach.
Twitter: The amount of followers the Twitter account had when the tweet was posted. Potential reach.
Facebook: The amount of followers/fans the Facebook page had when the entry was made. Potential reach.
YouTube: the amount of views the video has. This data is updates up to five days after the post has been collected. Definite reach.
Instagram: The amount of followers of the account posting the picture. This data is collected continuously. Potential reach.
Forum: Based on Alexa Reach divided by 1000. Alexa Reach displays the number of site visitors, and since a forum has thousands of threads, we divide that number by how many we estimate visit a specific thread. Potential reach.
*About Alexa Reach
Alexa is one of the most established tools for measuring reach. We do not have the exact formulas used, but it is of importance to understand that it does not present the definite reach. Alexa uses different factors to establish the number of visitors on a page. It is not possible to get more exact information than this, since this data is not public.