I'm not a fan of reading very long articles and most times I think some posts ought to be simplified and summarized to get ease of attention and from my observation, it seems most users confuse quantity with quality and think, writing very long post simply means the post has quality which is wrong.
I've seen very short and straight to the point post doing extremely very well on the forum and people ought to them learn from them.
Just as you have said, I am not really a fan of reading too much of a lengthy post mate but sometimes I take my time to do read them because there is always something in nothing to learn about. some people write lengthy posts while some are just as little as possible that they could do to communicate with their readers.
Really, some people try their best to summarize, their posts so as to enable people read it through but even at then, most do see reasons writing a lengthy post as it could be of help for them to make some little explanations for a better understanding of message being communicated. Sometimes, it could be as a result of requirements here. For instance those into signature campaign are expected to write a certain number of words to qualify and this sometimes requires some posters write lengthy post and still communicate. A lengthy post is not bad but let it pass across information it requires.