It is widely accepted that Web users scan Web pages rather than reading them in full.
We want to find the answer to what we are searching for, with minimum wasted effort and time. Life is short and time is expensive!
So, make your text scannable. Use bold headings, sub-headings and short paragraphs.
Try to get your message across with as few words as possible, without losing the value of what you're trying to say. As a general rule, in most documents you should be able to remove 25-50% of the words, without losing anything of real value!