The LessWrong blog is by and large a "feed" of new reader-contributed articles of interest to the community, called "posts" (to emphasize the original content) or "threads" (to emphasize the discussion that most often stems from the posts). There are some threads which serve a special purpose, mostly recognized by tradition:
These special threads are created periodically. (All links lead to the latest thread.)
Discussion threads created by Yudkowsky in the early days of LessWrong.