I recently started reading upon CDNs and how they can help optimize web requests by having a network of edge nodes which are much closer to the user.
What kind of parameters do CDN Providers look upon to determine where the edge node should be placed? Will it be just a look up of how many requests come from each region and then place more servers there or are there other factors as well like, maybe Facebook has a lot more requests coming from a particular part of Europe. To help them optimize their requests, a lot of edge nodes may be placed near them?
I realize this is a subjective question, but I am not sure where else I can ask this question!