Is there a research-level machine learning site in the StackExchange universe? I don't like Reddit's formatting system.
First of all, as already said in @gung's comment, CrossValidated is the site to ask questions on machine learning. Many machine learning questions (mostly those that focus on coding issues) are also asked and answered on Stack Overflow.
Moreover, if you search Area51, you'll see that there were already two proposals for "Machine Learning" sites, but they were closed mostly because of small traffic and a small number of active users.
Additionally, there is also a Data Science SE site, that has very similar scope to Cross Validated. We discussed it many times. The general conclusion of users of Cross Validated is that the Data Science site is redundant given Cross Validated, so the same would apply to any Machine Learning site.