The problems with cross-posting

I've written shorter versions of this many times, and rather than write it several times again in the future I thought I would centralize its location and just provide a link here. This article is for everyone who hasn't heard of the issues to do with cross posting.

To put it bluntly, cross-posting the same question to multiple forums can be considered poor forum etiquette. While some forums have strict rules against cross-posting, others are quite lenient about it, and the rules for each forum should be abided by should you wish your question to be answer politely and efficiently (JPF Crossposting Rules). Why is cross-posting considered poor etiquette?

1. Cross-posting on multiple forums without indicating so can result in wasting other members time. How? If your question was answered in one location, those elsewhere have no way of knowing this to be the case, and can spend their valuable time trying to answer a question which has already been answered. A good way to irk those who are trying to help, and a good way of hurting your chances of receiving help again.
   
2. Without knowing of other postings, the same questions, issues, etc… may be raised again and again on each forum. Important information in one forum may be neglected in others. All told, this chaos can end up wasting the time of those wishing to help and be confusing for you to top it off. If links to other posts are indicated and everyone is up to date - knowing the status of the question - you may actually receive an answer faster.
   
3. I once had an interesting question that I needed to solve. My first thought: google. Given the title of this posting one can probably guess what the top ten results were: ten posting to ten different forums all by the same user, all titled the same, and all with the same question. If I want to find an answer, I would rather not wade through dozens of identical posts across the internet to find it. Bottom line: cross posting multiplies the amount of information (useful or not) others must wade through to search for a solution.
   
4. Those spending their free time, unpaid, trying to help can find it rude if one neglects any of the above. They have reason to do so, and have a valid reason to ignore your question and quickly move on to another should they suspect they may end up wasting their time.

On many forums, members may post cross-posting links for you. Sometimes new comers might think this as rude behavior on their part, or just not understand the reason, but read the above and consider it from the other side of the coin. Perhaps another way to think about it: would you rather a member spend time on your question, or on some one else's which was already answered somewhere else, and the response they are writing may never even be read?