I think Stack Exchange A.I. site is self-promoted and it does not need promotion. We just need a bit more time, that's all. I think this site has enough active experts so far, so our answer ratio is fine (1.8 at the time of writing).
Secondly given Stack Exchange higher ranked SEO abilities, people looking for A.I. answers will quickly find this place. Especially having in mind that A.I. is more likely to be the next big boom for this century, I believe next year we'll hit the site healthy stats without even promoting it.
Although if we decide to promote it, we need to be careful, as promoting this site to the wrong communities, this can result in lot of people asking the broad and opinion based posts.
Artificial promotion isn't a good one, but sharing the AI links to the good answers on relevant forum posts or reddit-like sites is a great start.