TheOptimizationIdiot - 1:43 pm on Apr 8, 2013 (gmt 0)
I've heard the same thing, but have one that's been in the top 10 for the last 5 years, only gets registered for one year at a time and actually had the registration expire last December due to a credit card not getting updated.
It wasn't reregistered again until after being deindexed, but within a week of being reregistered and reindexed it was back in the top 10. It was once again only registered for one year.
Registration length makes no difference at all.