tedster - 5:26 pm on Jul 15, 2010 (gmt 0)
The link data that Google reports used to get updated once a month at best, so the current situation is progress.
Why does it update by bits? I'd say the main issue is one of scale. The web holds a seriously large number of ever-changing links. The closer Google can get to "real time" updates, the more accurate and actionable the data would be. But they will always put more priority on the SERPs rather than webmaster reporting.