SearchMetrics, which is a pretty solid tool when tracking how websites are doing when various Google updates touch down, added a neat new feature to their charts.
You can now see, on the chart, the various Google updates overlaid on top of the graph. For example, in the chart below, you will see for my site, that we got nailed by Panda 4.1 (as you know).
You can click on the chart to enlarge it. So now, even non experts can see quickly which Google update may have resulted in their site dropping in Google.
It is a small change to SearchMetrics, but it is a very useful one. Many of the other reporting tools do offer this but I find SearchMetrics to be one of the more accurate ones.
Glenn Gabe posted this on Google+ and said New in "Searchmetrics, Google updates in search trending (which are clickable). Nice addition." Agreed.
You can toggle them on or off by clicking on the Google box under the graph.
Forum discussion at Google+.