What pie charts are good at is providing a visual comparison of a series of values that compose a whole. Pie charts work when you're trying to represent a percentage of a total value. The example in the link about "features" is crap because unless you're given a value of "100 features were implemented across these versions" the comparison that Word 2000 and 2003 provided similar values is meaningless.

Its not that you shouldn't use a pie chart, it is just about knowing when to use the pie chart to represent your data