Having more than once emphasized the need for careful proofreading, I have to concede that in many cases, "correct" spelling or usage is simply a matter of majority opinion. Web site or website? Lois' report or Lois's report? Peas, beans, and bacon or peas, beans and bacon? Even the style guides don't always agree.
The worst headaches come at those points where officially accepted usage is in transition. Most over-forty keyboarders remember the old typing rule about leaving two spaces between sentences and around quotation marks--and having to adjust to one space with the rise of word processing. Now, the shift from Web site to website has writers once again fuming over the need to develop new habits. Many a writer-vs.-editor, author-vs.-coauthor, and blogger-vs.-commenter argument starts because both parties are technically "right" (each according to a different style manual or dictionary) and each is positive he or she has the only right way. It's not only in matters of ethics and theology that enemies are made because one person's obvious fact is another person's inexcusable lack of tolerance.
It won't help to wish for permanent, fixed agreement on every point of the English language; even if such were possible momentarily, a living language can no more be stopped from changing than can a living organism. Comparing "proper" English from country to country, dictionary edition to dictionary edition, or century to century should convince any thinking person of the futility of demanding lasting consensus. (Believe it or not, double negatives--"I don't have no apples"--were once grammatically correct; and once upon a time girl simply meant "youngster" and could include males.) If nothing else, the need of new words for new inventions would ensure that English in 300 years will follow different rules from English today.
In the meantime, we still have decisions to make. So here are a few rules that aren't likely to go out of date:
Be consistent. Write Web site once, and consider yourself committed to it for the rest of the document. Better that readers should think you're out of date than that you're too scatterbrained to have an opinion. And if you use a style manual, consult the same one--and the same edition--every time.
Look it up. If there's the slightest doubt in your mind, defer to a recognized reference source. "It's in the Chicago Manual of Style" carries more weight in a disagreement than "I've always done it this way."
Give a little. Complaining about your supervisor's dictionary preference or stubbornly insisting on the last word is unprofessional behavior even if your writing is technically correct. If anyone is firmly committed to a spelling or form that does have some official recognition, better to go along with it than to demand majority rights.
Don't make a big deal out of every criticism. Not only is it impossible to be universally correct on every point, but anyone who writes for wide distribution (especially in social networking) will eventually meet one of those stubborn souls who are positive they're right even when every reference source disagrees. Don't waste energy defending yourself to the last breath; know when to ignore an accusation, or say politely "I'll think about it" and move on.
Even the best writers can't always be right in everyone's eyes; but we can always be accepting of everyone's right to an opinion!