Can anyone fill me in on what Verisign actually does? It's my understanding that ICANN ensures that the namespace/numerical space infra is secure and stable.
* Manage the database of all domain registrations in a TLD, and manage the infrastructure that registrars (the companies that customers actually interface with) use to create and update those records.
* Manage whois, although IIRC .com and .net use a "thin whois" model where the TLD whois server redirects to a whois server run by that domain's registrar.
* Run the authoritative DNS servers. This is the most critical component, since if the authoritative servers for .com and .net went down, it would basically be an "Internet outage" - an enormous amount of things would break if recursive DNS servers couldn't resolve .com or .net domains.
It's an important function, but as others have pointed out, it doesn't justify the price increase, Verisign's profit margins are huge. And the fact is that Verisign doesn't actually own .com or .net, they're basically a contractor for ICANN.