I like the "PerfCharts" at stockcharts.com, which has the same feature. Plus, you can click on one of the stock/fund names and see the relative performance of all others to that stock/fund. That was handy when I was trying to divest a bunch of company stock. They may have less historical data.
I'm pretty sure Yahoo's charts only show fund prices, not total return with dividend reinvestment. It seems like some of the funds at stockcharts.com have the total return, but some don't for sure. That makes it very difficult to compare fund performance.
Does anyone have a favorite chart site with total return curves and multi-fund comparison? Morningstar kind of falls short on the comparison side. Fidelity can chart a few funds with total returns, though their Morningstar data seems a little dated.