tedster - 3:52 pm on Jul 27, 2012 (gmt 0)

why would there be a need for deep crawl at the time of algo refresh?

Here's how I understand it. There are two types of Panda changes - a DATA refresh and an ALGO update. There is a need for a new deep crawl around a data refresh, which this is. New data about websites is fundamental for a data refresh.