CardioLog can identify anonymous users by their workstation IP address, or by creating a unique id and storing it in a browser cookie.
Using IP address
Pros - Enables individual IPs in reports, works when browser cookies are disabled.
Cons - When using a proxy/VPN in order to access the internal network, the CardioLog tracking agent will not be able to get the client workstation IP, and the registered IP will be the proxy IP. In this case the unique users metric is inaccurate.
Note: CardioLog collects the workstation IP anyway, for geographic location.
Using unique ID
Pros - The most accurate method for identifying unique anonymous users, even when using proxy/VPN.
Cons - When a visitor deletes his cookies, the next visit will generate a new unique ID. When cookies are disabled, each visit generates a new unique ID. When a visitor uses multiple browsers, such as Internet Explorer and Firefox, a unique ID will be generated for each browser.
Note: by default, the user name will be a unique id in the following format - "Anonymous_XXXX"