Those likely aren't long-term real domains. Directnic (and a few other registrars) have been playing a game of registering hundreds of thousands of domains daily, testing them for traffic, and then deleting 99.9% of the domains that don't get traffic within the initial 5-day deletion grace period.
You can see this at
http://www.dailychanges.com/ if you check back for 5 days in a row.