Anne Zelenka posted on the Web Worker Daily: Are You a Filer or a Piler? In particular she references: Surviving the Information Explosion: How People Find Their Electronic Information (pdf) by Christine Alvarado, Jaime Teevan, Mark S. Ackerman and David Karger.
I used to think that email pilers were just lazy. Why couldn't they spend the extra few seconds to drag the email into a folder? My work was client/matter related. With an email folder for each matter, it was easy to figure out that an email for a particular matter should go in the email folder for that matter.
When I set up my Gmail account, I was stunned to find that there were no folders to file emails. Just one long inbox. Clearly it was designed by those lazy pilers.
As I continued to spend more time in the knowledge management department, my km emails became harder to pigeonhole into a single folder. I even found that I was inadvertently creating a new folder in the hierarchy that I had already created somewhere else.
So I came around to see that piling is a legitimate practice. (I still think many pilers are just lazy.)