My concern is, that while this comparison is useful for people further along in their research trying to understand the volatility of the stock market, this chart has a number of misleading (IMO) traits that can dangerously/unfairly steer people who are newer to managing their own money away from index funds altogether.
I would hope that people see this chart, my comment, yours, and FabHK's excellent comparison to bond yields. But if you have limited attention and are getting started, I would hate for the original link to be the only thing you see.
Speaking for experience with family and friends, too many good people scared by charts like this bought gold in 2011 or trusted mutual fund managers to buy into funds with 4% front-end loads and 2% AUM fees.