Back in the day, Network Solutions was the only game in town. They sent out paper invoices and they charged $100/domain/year. Fast forward 10 years: their rates have dropped, they no longer send out paper. They added two new gotchas. First off, when your domain expires they reset your DNS to a domain of their choosing. Second, the new resolution links to one of their godforsaken spam ad sites.
In the past, they would let your site drop into limbo and come back when you paid and the DNS proliferated. Because they continued to belt out the DNS, the SOA looks fine. If you were a bandwidth and processing conscious sysadmin, wouldn't you do the bare minimum with regard to fetching DNS updates? That plays into the hands of Network Solutions.
In a spazzy and technically inept attempt to push through changes, Network Solutions resets SOA TTL to one second. That's the equivalent of spamming. Most DNS servers are configured to reject TTL values which are too low to prevent unreasonable amounts of DNS traffic on the Internet. Network Solutions is so incompetent that they are actually hindering proliferation of sites they register. In short: if you use Network Solutions, your site may be harder to find. Rather than propagate a change worldwide in 24 hrs; it will stymie change for some time.
There is good news: one of Network Solutions' weasely practices has been challenged in a lawsuit. The practice of Front Running-- locking in a domain you search for in case you come back and register it later-- is now the subject of a lawsuit. After suffering their other weasely practices, I hope they choke on this lawsuit.
Until you can join others in an appropriate lawsuit and sue Network Solutions into the first dimension, my suggestion is STAY AWAY FROM Network Solutions. For me, I'm fond of Dotster.