Receiving comments on one's article
I'm aware of three general approaches that seem to be currently effective for seeding such discussion.  Listed in order from most direct to least direct:


Comments hosted by the journal itself: a number of journals that are embracing open science principles are embracing commentary directly.  With this, you don't need to take your article anywhere else for people to comment on it: they can do so right there at the article.  Examples of this approach include PLOS ONE and the Frontiers series.
Some sites, most notably PubPeer, are explicitly intended to support discussion of articles.
If you've got a blog or other social media site, you can also host discussion there.  For some people, this can be very effective, but you generally must already have a significant audience in order for this to be an effective strategy.


In all case, however, it still tends to be difficult to get meaningful discussion going of most articles, since academics don't seem very interested in comments sections unless there's a fight going on...