The Resolution Solution

Scott Bourne at This Week in Photography has posted an article titled "Resolution Solution" which aims to clear up the confusion between PPI, DPI, and LPI.  He takes the simplistic approach of recommending that people memorize when to use each term.  Although this doesn't explain the fundamental differences between the units of measure so one will understand why we use a particular unit with a particular device, it will at least help people use the correct unit for the device they're talking about and may help eliminate confusion when reading or listening to someone else speak on the subject.