Thanks Ryan for providing that link to Silent Doug's explanation page.
Thought I'd mention that everyone does this their own way, and I don't
use exactly the same system that Doug describes. For example, if a box
changes its stamp AND location, I count it as a new find. Also, I only
count as a find a box where I have been able to swap images, so if the
box is there but the stamp is missing, I don't count it. I also have a
list of "A" boxes, which is where I'm reasonably sure I've found the
correct hiding spot, but the box is gone (A=attempted). Tara keeps a
list of "D" boxes - those that she has found in her dreams! There's
also a new trend of Postal letterboxes, which I call PLB to distinguish
them from my regular P count. And finally, I keep an S count - number
of states where I've letterboxed. There are merit badges you can get
for almost all of these categories.

You guys are so lucky - I don't think there were 100 letterboxes in all
of California when I started and it took me a long time to reach that
hurdle! Keep on boxing, and I'll see you in April when we'll all
increase our X and E counts.

Princess Lea
P71 F359 X86 A26 E10 Plb4 S9