The wiki is for stable reference content; you'll notice much of it is definitions of terms, lists of posts for easy reference, and summaries of concepts. The discussion tab on the wiki is used mostly for editors to talk with each other, which very rarely happens.

If you want to have a conversation, posting in the current open thread is probably the best thing to do. (The next step, if you have something long enough to talk about, is posting a post in discussion, which you do by hitting "create new article" to the right of your name and karma display.)