Punctuating Bullet Lists

While this tutorial on using bullets and bullet lists addresses several design issues including bullet size and spacing, it doesn't address punctuation. In the forum mezzo4life asked, "What is the appropriate punctuation for bulleted sentence fragments under a heading on a PowerPoint slide?" which has led to a discussion of just when to use or not use periods and other punctuation in bulleted lists - whether in PowerPoint or in print. I found some online references which seem to contradict some of what I'd always believed about bulleted list punctuation. Seems several forum members disagree with the cited article and raise questions that it doesn't seem to address. So, what do you think?