Vanilla 1 is no longer supported or maintained. If you need a copy, you can get it here.
This has been bothering me - how can I get sub-categories/sub-forums on Vanilla? I believe there used to be a plugin for Vanilla 2, and I know there's one for Vanilla 1. Could someone write a plugin to do this please - or tell me how to achieve this? (i.e. the way phpBB has sub-forums on the first page, and you have to click on one of them to make a post.)