you make it sound like the purpose of writing an article is to post it on some other website like ezine.com, which has the following welcoming message plastered across its home page:
Submit Your High Quality Unique Articles To EzineArticles.com
In Exchange For Traffic & Exposure Back To Your Website!
if that’s what you think article writing is all about, i feel sorrry for you
this is not the seo forum, by the way
Hi r937,
Each one has their own purpose to write article. Some one writes article to brand their product, some writes article to create awareness among the people and some may use it to increase the traffic for their website. So the purpose may vary for each one.
Some interesting points here and all with a level of validity. I did, however, only see one truly salient point which was made by Shyflower. The “visitor” is the crucial element. What is the topic of the page? What information will people wish to absorb quickly and how deep might they like to dig (at a slower pace)? In my opinion the question “how many words should a web page have” is actually the problem… the question actually is “how big should the website be?” How much weight, or credibility should it have? If you are offering up a subject matter, do you really, honestly expect that learning experience to be over in a single page? A good website commands the subject matter on a global scale - it must be a resource journey that educates, helps and invites further discussions and learning… just as a helpful human being would.
More short & concise your article will be more traffic you will get accordingly. Please make sure of only one thing that your article topic & content should be unique & attractive as people like original & different articles. Length doesn’t matter.
I agree with most of the replies to this thread, there is no “Magic length number” just like their isn’t magic topic heading. I guess it comes down to your own writing style, and most importantly who you are writing for? If you’re writing articles for visitors your primary goal should be to write a “good” article, including all your points/values on the topic without dwelling on trivial matters (that inevitably add length).
But again, there is no answer to your post, there’s only a bunch of opinions 
Mine is that you should focus on the quality of the article, and the length will have to stretch itself accordingly.