Sand - 7:41 pm on Nov 6, 2012 (gmt 0)

@petehall,
Refreshes can be pretty mild, because there aren't any changes to the Panda algorithm itself. Updates are like a net being trolled through the water, catching stuff as it follows a pre-defined path.

Updates are generally more significant & impact more queries, because that's when they modify the criteria of what qualifies sites for the filter.