I had a houseguest for a few days recently, a long-time reader who has only written a handful of comments, and I commented to him that the quality of discussion on LW is worse than it has ever been, and his reply was, "Well, yeah if you are talking about WrongBot."

I think your houseguest might not have read a representative selection of LW posts; their assessment doesn't ring true for me. I haven't read WrongBot's top-level posts closely (nothing personal - the evolutionary psychology stuff just isn't that interesting to me), but I've skimmed through the resulting threads/comments on them as they've passed through Recent Comments, and they honestly don't look all that bad.

I can think of a few recent posts/discussion topics that I am fairly confident have lower quality than WrongBot's:

• '(One reason) why capitalism is much maligned'
• Daniel_Burfoot's quite rambling series of posts that uses 7000 words just to talk up data compression as an add-on to the scientific method
• whpearson's bit of evolutionary psychology 'Summer vs Winter Strategies'
• MBlume's link to 'Jinnetic Engineering' - the content is good, but it's not meaty enough for a top-level post IMO
• the string of posts a while back dancing around the Sleeping Beauty puzzle and what it meant - there was a lot of good in them, and their comments, but the discussions got really flabby really fast