I noticed those comments were gone as well, though I'm not sure what happened to them. In general, I see certain threads as being blessedly devoid of conversation: stuff like Cool Lyrics and Cool things on the Internet. These are threads that I can go to and find, well, cool lyrics and cool things on the Internet, and I know that I can read them all without having to wade though a bunch of dialogue to get to them. I don't mind when the occasional person pops in and says "ooh, I like that song," but big discussions feel out of place in those threads and others like them.
That said, I don't know to what level we should enforce non-discussion, or if we should enforce it at all. For me, I'm totally happy creating a separate thread to discuss how much I hate a lyric rather than "spoiling the purity" of the lyric thread itself, but I realize that not everyone shares that opinion. I'd like to see what other opinions there are (assuming more people see this thread and make their opinions known).