Of course. Pie charts look natural and easy to comprehend when visualizing things like market share of certain products, for example browser market share (http://www.netmarketshare.com/browser-market-share.aspx?qpri...). In fact I'd argue that that's a much better representation than a bar chart, like http://www.w3counter.com/globalstats.php, because the former makes it easier to comprehend roughly what proportion of the total market each browser represents, which is not as straightforward to see in a bar chart (in bar chart it's only easy to see how different browser market shares compare to each other). So yes, pie charts may be appropriate at times, although I agree that it's a poor choice in this particular case, as the root comment explains.