I'm one of those mappers from Cartographers' Guild - just dropped in to say "Hi". I have no doubt I create maps really not of your flavor.
CG was actually introduced to the Conquer Club from a member named Widowmaker, from back in April...
http://forum.cartographersguild.com/showthread.php?t=1738&highlight=conquer+clubWhich we thought were some awesome maps!
The idea of collaboration between our sites sounds cool, except, your comments throughout this thread is correct in thinking our maps and your maps are completely different animals, though I think we can both appreciate the work each performs.
Though many, like myself, post maps with no collaboration at all, many newbie mappers post their first entry and immediately an army of CG mappers descend to offer tips, ideas, and mini-tutorials within many posts - so their is some level of collaboration.
I really lack the time myself to collaborate as I spend most of my non-work time, creating commission paid for maps for small RPG publishers and individual game masters.
I'm also sure, I'm a user of software, no here has heard of, truth tell, only 2 other members at CG use's as well. Xara Xtreme 4.0 - kind of raster/vector hybrid application, inexpensive, but not free, like GIMP or Inkscape. I use it in my daytime graphics/digital printshop, so its my choice for mapping as well.
Most of my maps are much higher resolution than those found here, but then I'm spoiled in owning a 42" wide large format inkjet printer - so my map designs are generally intended for printed output, not for use online.
However, I have been doing commission and contest mapwork strictly for Virtual Tabletop applications, like MapTools - online sharing of maps, chat, messages to play a tabletop game like Dungeons & Dragons with a group of friends or participants around the world.
I also operate Gamer-Printshop a website dedicated to printing large format color and black and white maps for individuals and publishers. I've become a print-on-demand shop where cartographers post their wares (add markup to printing and shipping costs I apply) to sell to clients around the world.
Again, not you're kind of maps, but here's my partial portfolio of maps...
RPG Map PortfolioAnyway, just saying, "Hello".
GP