IP address retargeting
This option would be very useful for those advertisers selling business services. e.g. if one person from Law Firm XYZ browses my product page, I'd like to be able to advertise my product to all browsers at Law Firm XYZ. Of course, this model works less well when serving ads to large heterogeneous organizations, but for smaller more homogeneous businesses, IP-based targeting can be quite effective.
As for PII concerns: At the corporate level, IP Address does not serve as PII because anywhere from dozens to thousands of people will sit behind the same proxy/firewall and broadcast the same IP address to the world. As the home/consumer level, any time a cable modem is rebooted the IP address is reset. In any event, for IP based targeting I am not interested in the home/consumer market, so you can just exclude those IP's that map to non-corporate users.
ElToro.com does exactly this.
Rich Quarles commented
I agree, this would be great.
It looks like a new company El Toro is built specifically around offering its clients IP Adress targeting.
Thank you for the feedback. This is not something we're supporting at the moment, but it definitely has been added to our list of features we'd like to add in the future.
Was this implemented? This is a MUST today! I will hire perfect audience immediately if this was implemented