I made some custom campaigns a long time ago... lol I think it was about a decade ago. Sometimes, if what you made is good enough it will spread on its own. I abandoned that game and to my surprise, years after, people are still uploading my maps. One site went down, someone still had my map files and uploaded it to other sites. There were russian, chinese sites where I found my maps. I don't understand the language but the title is the same and luckily they're gracious enough to keep me as the author (english characters).
You can have an official site or other sites but IMO your work will spread on its own. An official site is okay and there should be one. However the community will decide which is better and will naturally flock to it.
I hope that Larian will not attempt to control the modders/map makers/campaign makers etc. I hope that the files are easy to export, save and anyone can easily play them regardless where they got it. For example, I think Blizzard tried to control this outflow with Starcraft II. They had a central server which all custom maps should be uploaded and published. People had to go through these absurd work-arounds to play certain custom games. This was a far cry from Warcraft III. Just one click and you're off.
