The compete data only estimates traffic from url redirection, not including traffic using Domain Sponsor DNS (which is the preferred way of sending traffic for several reasons…)

I don’t have a DS account although almost all of my names are registered at Moniker. I didn’t realize that was happening… The graph was interesting, but the more interesting thing, IMO, is just how much traffic that one url has – and I am sure if you added the other dns that people use it would be much higher. It’s no wonder they’re a domain industry powerhouse!

We can infer from the graph that less traffic is being redirected to DomainSponsor now than was earlier in the year. There have been rumors about google not wanting their parking partners to use url redirect any more, so perhaps some (large) parking customers have switched to using their nameservers.