Nice list! I don't agree totally, but I hate the quote trees the most: unless they're totally needed to understand the discussion (for example if the last quoted post is some pages back and not easily findable) they are annoying. The necessity to follow the thread or subthread can be satisfied with one long quote every one or two pages, but the successive comments can have the tree trimmed to the last few posts. Also, most times, just a part of the previous posts needs to be quoted.
BTW I'm sometimes guilty too of not trimming those trees enough, sorry.







