Google Penalty World

Mozcast is a free data reporting service which allows you to see general trends and symptoms indicating whether Google is making significant changes to its search ranking algorithms.

MozCast has been designed to help you keep track of the day-to-day changes in the Google algorithm by tracking a hand-picked set of 1,000 keywords and by grabbing the top 10 Google organic results.

These are compared with the previous day's top 10 (for any given keyword), to produce something that looks like a temperature (in °F). An average day is about 70°F.

Free to consult.

Try it out now: http://mozcast.com/

Learn more about how it works: http://mozcast.com/about

(Thanks to Donnie Strompf for kindly suggesting it)