adnxs.com is a domain used by AppNexus which is an advertising company that is part of a network of sites, cookies, and other technologies used to track you, what you do and what you click on, as you go from site to site, surfing the Web. Over time, sites like adnxs.com can help make an online profile of you usually including the sites you visit, your searches, purchases, and other behavior. Your profile can then be exchanged and sold between various companies like adnxs.com as well as being sold to other advertisers and marketers.
More about AppNexus:
Real-time bidding will be a multi-million dollar business in the next five years. Ad networks, demand-side platforms, trade desks and other leading online advertising companies need a core competency in RTB – and a fully white labeled, open API-driven platform designed especially for their needs. These companies, including eight of the top 15 ad networks, are increasingly tapping AppNexus (comScore, June 2010).
Sites using adnxs.com to track you: