As traffic leaves Tor's "Onion Routing" feature, the traffic must exit through another connection, usually a web server. One drawback of the Tor network, is that this web server can monitor the traffic that is being routed through it, but it's very hard for one entity to control many active tor exits since so many are available. The Tor exit server's IP address is what a website or company would see when a Tor user visits their website or makes a purchase online.