If facebook is like twitter in that regard, I mostly wouldn't expect you to get feedback about an article having been read - but I'd also not expect an especially high probability that the intended person actually read it, either. What I meant was more along the lines of emailing/IMing them individually with the relevant link. (Obviously this doesn't work too well if you know a whole lot of people who you think should read a particular article. I can't advise about that situation - my social circle is too small for me to run into it.)
Sorry for the delayed reply...
I don't know what Twitter is like, but the function on Facebook that I prefer to use (private messages) is almost like email and seems to be replacing email among much of my social circle. I will preferentially send my friends FB messages instead of emails, since I usually get a reply faster.
Writing on someone's wall is public, and might result in a slower reply because it seems less urgent. But it's still directed at a particular person, and it would be considered rude not to reply at all. But when I post an article or link, the reply I often get is "thanks, looks neat, I'll read that later."
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
If continuing the discussion becomes impractical, that means you win at open threads; a celebratory top-level post on the topic is traditional.