I came looking for this information and the following (from the link posted by Exquisite above) helped me. I purchased the game through Steam, but I believe the info below will work for anyone looking for their 'Community' folder. I'm currently running 22.214.171.124.
- Launch the game and go to the Options page
- Click on General
- Down the left side, select 'Developers' and set Developer Mode ON
- At the top of the screen there will be some small menus. Go to Tools > Virtual File System
- The path of your Community folder is under "Watched Bases". There may be a number of items here - look for the one that ends with "Community".