This has two and a half effects. The most obvious is political—if ICANN rather than VRSN is distributing the root zone, it removes the symbolic significance of VeriSign running some of the root servers. The second is DNSSEC key management. Until now, the contents of the root zone have been pretty boring, a list of names and IP addresses of name servers. If DNSSEC is deployed in the root, which is not unlikely in the next few months, ICANN rather than VeriSign will hold the crypto keys used to sign the root zone. If a tug of war develops, whoever holds the keys wins, since without the keys, you can't publish a new version of the root with changed or added records unless you publish your own competing set of keys and can persuade people to use them. (Take that, ORSC.)

The half thing is that the agreement requires that when VeriSign sends ICANN zone info updates, ICANN has to apply them within a week. Since IANA has been taking a month to handle updates, this means IANA will have to get their act together enough to provide bad rather than horrible service on domain updates unless they provide a special express channel for TLDs that have contracts with ICANN, and give the current horrible service to everyone else.