How many people can use the WebServer software?

The Web Server usually resides on a LAN server and only one license is required per server.  Multiple QA users can "publish" charts to a web site through one Web Server over a LAN.

The only reason someone would need more than one Web Server license is if they have multiple facilities and have a web site at each facility, or provide content from each facility to a single web site over a WAN.  In the second case, it is possible to locate a single copy of the Web Server where the web site is and have it get its data or graphics from remote facilities over the WAN - however, there are performance and administration issues that don't always make this the best idea.