As a mainly business site we always brace ourselves for a significant drop in accesses during US holidays. And this always seem to impact the day before and after as well. Maybe leisure oriented or maybe even shopping sites would be different.
There is a real week-to 10 day-long lull in the business world here from a couple of days before Christmas until January 2. After that, things get back to normal. Unless you're in New Orleans, where we have Mardi Gras, the Final Four (college basketball), and a couple of other major events in the first quarter of the year.