I've been thinking about this post for awhile. I take the colors in the same way I believe they were intended, to show the length of time/participation in the forum. I liken it to being at my place of employment. I just moved into a new group and am learning a new job. Obviously, everyone there has been in the group longer than I have. Some as much as 10 years, some as little as 3 months. Everyone has varying degrees of experience, but it doesn't necessarily mean the person who's been there the longest is the most equipped to train me personally. Could be, could not be. If possible, I learn what I can from each person and try to minimize my interactions with ones whose energy doesn't mesh well with mine. In some cases, someone who has been there for a shorter amount of time is actually very knowledgeable about certain things and I can gain from them. Also, because I've only been in the group for a few weeks, it doesn't mean I don't have experience elsewhere that could benefit myself and others in this role.
If I personally apply that to the forum, I may pull my learnings from blue, green, orange and white. But not all or none of any of those. There are some blues, greens and oranges who I read everything they write and can relate to/believe 99% of what they say. There are some blues, greens and oranges who's posts or advice don't resonate well with me, so while I appreciate anyone willing to post a response, I move on to find something that does sit well with me. And some in between. I think people are very smart and can see for themselves who is posting thoughtful, insightful and guiding posts, regardless of color. I myself am going to learn from someone not only giving the answer to my question, but also a reason why they have found that be the case. I am less likely to put stock in a response from someone who asserts somethings as fact without reason/back-up, regardless of what color their username is. I know others learn differently and that's the beauty of a forum as diverse as this.
Someone (and I apologize, I don't remember who it was) posted some informal guidelines for the forum that I came across when I first started using the forum and one of the first items on the list was something about color not necessarily dictating how knowledgeable someone is. I've always kept that in mind and try to judge someone's experience based not only on how they present their knowledge, but also in the way they treat other people rather than color.
Just my two cents