This is the best and most comprehensive explanation for why my HTC Incredible keeps getting low storage warnings when it does not look like there should be a problem. What it does NOT explain is why HTC decided to make the Application Data Storage for the phone so small and non-configurable. With 748MB of App Storage and 6.6GB of phone memory, which on my phone never gets used because of the SD card, why can this teeny tiny 149 MB partition not be expanded to accomodate more. With more and more apps requiring usernames and passwords and the ability to use your phone as your mobile pc it is inevitable that this partition is going to get filled up fast.
This morning I was on the cusp of doing another hard reset on my phone when I decided to go into each app, one by one, to see just how much data is being used. Thankfully with Gingerbread 2.3 build 4.08 it is much easier to see at a glance which of your apps is a data hog and clear it.