As you know, it is possible to overlay the same destination number multiple times by providing different reference strings. This feature can be used to track call statistics from different sources separately. Users have used this feature to compare call data to the same companies from different websites and to see how many calls are generated by different versions of a piece of software.
While this system works, if you have a large number of sources or a high call volume it can be tedious to separate out the data. By setting up advertisers within the ADNOS system (see Advertiser functions for details) it is possible to let ADNOS do this filtering for you. Just specify which advertiser an overlay should be attributed to when requesting an overlay, and all calls will be flagged as such in the ADNOS statistics.
Note, passing the name of the advertiser is supported for legacy reasons. As it is possible to rename advertisers via other functions it is strongly recommended that you provide the advertiserID where possible.