This was a fun thing I stumbled across the other day: it's called POBox Archives, a Tumblr joint effort between Julie Doucet and Simon Bosse (a talented Quebec cartoonist). Most of them are from fans or other cartoonists, and harken back to the early 90s hey-day of Doucet's Dirty Plotte fame, which she has gone to great lengths to distance herself from in the 20 odd years since.
There's a ton of fun stuff here, including postcards to Simon from Marc Bell (below), and one to Julie Doucet from cartoonist Jean-Christophe Menu from the early 90s, when he was about to establish the influential comics house L'Association.
check that one out. Here's the front:
It's only been up and running a couple of months, but I look forward to this weird peek into the past.