Dave Winer on disclaimers:
I sometimes shake my head wondering why some weblogs so openly say things that are just plain wrong, that are so easily refuted, without presenting the opposing data, or even suggesting it might exist with a disclaimer like imho, or ymmv, or ianal.
I'll just address the last bit, about using acronymic disclaimers and the other part perhaps elsewhere. The reason many don't use them is the same reason we were taught not to write "I feel" in high school: it's obvious when an opinion is an opinion because adjectives (or the words "should" or "must") are used.
This is not a problem limited to weblogs, however: watching soundbites of 'people on the street' who oppose the war on Iraq is an example of this. The problem is not that they opposed the war (although I disagree with them), but rather that people just disagreed with it without saying why! Typical statements are "I feel we shouldn't go about invading other countries." A perfectly legitimate opinion, but it's not enough to convince someone who holds the opposing opinion. A more complete (and convincing) argument—even if in soundbite or weblog form—might go something like this: "I feel we shouldn't go about invading other countries, because it makes us look bad | because of military overstretch | because we might lose more than we bargained for." (I have problems with moral arguments in general too, since, well, nobody likes being told what to do.)
The IANAL is a recent favourite of mine, since, well, not being a lawyer doesn't make one's opinion less or more valid, and besides, would you take law advice or accept a legal opinion from somebody who openly admits to not being a lawyer?
Anyway, if Dave is saying that one should be humble in their opinions and express that humility (regularly claiming unoriginality is a hobby of mine), then I'm all for it. But false humility (false modesty's twin brother), is a very unattractive quality in a person, because, by definition, it's fake, and only really serves to call attention to the person in question.