Hexenbracken would be followed with another collaborative project; in this case, the Kraal. I was in pretty heavily on this one, and I want to talk a bit about what I saw from watching it be created, because I think it's a fun way to create something that is actually usable.
One of the big advantages of Gygaxian Democracy is that good ideas get picked up and run with; people are very thoughtful about building on adjacent and even non-adjacent hexes, reusing races and minor variants. Ice Goblins, White Elves, even Ice Weasels populate the Kraal. There are sabre-toothed cats (smilodons) and mastodons and other appropriately arctic things. Each of these things grows in a very nice fashion. But the basic issue with the fill pattern is that the ideas are only partly developed in the left corner, and as you move to the right of the map they get more systematic and the ideas get more well-integrated. It strikes me that the way to remedy this would be a fill pattern that skips around, building up 4 or 5 subregions bit by bit - for instance, going between the four quadrants of the map in a cycle. This could be done pretty easily using a web application to offer the next hex that needs to be filled; it would also solve the problem of having to reserve a hex and running up against duplicates and missed hexes.
I think the fact that the Kraal decided early on to be arctic really improved the nature of the experiment, because having that simple parameter meant that everyone involved was offering their take on a fairly coherent basis rather than simply slapping together wholly incompatible bits. I also like that it was decided on the basis of the first handful of posts - that is, even the vision followed the democratic norms. The low bar for participation really brings out some folks' creativity, in the best ways.
Using this approach seems particularly well suited to a hexmap, where there should be a diverse but generally related set of things. I don't think it's necessarily going to revolutionize the way gaming settings are done, but it's new and it's a heck of a lot of fun. If it keeps going, I might be interested in doing a rare not-for-work programming project and working up a web form to run Hexenbracken/Kraal style Gygaxian Democracy projects.
But in the mean time, get in on this! It's a great trend and I'm very interested to see what else comes up.