The information the demand source tag includes things such as domain name, ad size, among other things. Most of this information is publicly available--take a look at the AppNexus public wiki for more information.
This is generally something that only online ad professionals can pull off, but if you have enough of a bankroll, you can try it as well. It's a very saturated space and the amount of knowledge that goes into it is much more than what I'm able to include in a forum such as this. Good luck.
This is generally something that only online ad professionals can pull off, but if you have enough of a bankroll, you can try it as well. It's a very saturated space and the amount of knowledge that goes into it is much more than what I'm able to include in a forum such as this. Good luck.