Friendly message forum concentrating mainly on horse racing, but also including threads on other sports. In order to view posts you’ll need to register as a member.
At the time of writing they didn’t have that many members, but they’re actively looking to increase numbers.
The forum includes a private R&D area, for members to develop their systems, with the assistance of others. This area is hidden from members who don’t post, so you’ll need to make a certain number of helpful posts, before you can gain access.