SEOmoz announced a new neat service that aims at providing insight into if Google has run a major search index/algorithm update in the past by tracking 1,000 keywords every 24 hours from a select number of web sites. The service is called MozCast and literally shows a weather report based on ranking fluctuations.
It is updated daily for the previous day around 7:30am Pacific. Based on the fluctuations in the Google search results from the previous day, it will show a temperature and weather symbol:
The weather report for Monday was 68 degrees, which is fairly normal. When you hit 90 degrees or higher, then you would expect a major ranking algorithm change to be announced or had been announced by Google. The tool also shows the past 5 days on the left hand bar and the past 30 days in a chart below. It also documents the major events since the tool started tracking.
I was an early beta tester of this tool, since I personally carefully watch the Google rankings and provide human based Google update reports. There were times during the beta period where we didn’t agree on if there was a Google update but I’d say most of the time, we both agreed there was a major fluctuation in Google.
I should mention, SEOmoz is not the only one automating this reports, SERPmetrics has been doing this for a long time.
For more details on how this works, see this page.