A couple of weeks ago I read an article on the NY Times blog section of their website written by one of their columnists. I was shocked to find the post rife with spelling mistakes. Not only was this distracting, but immediately led me to question the writer’s credibility.
It's easy to change websites and post information. In the past, it usually passed by several people before making it live on a website. Nowadays, most websites allow an individual to post immediately and from many different places (including phones). The disadvantage to this immediacy is the increased likelihood of errors.
In fact on this site all the guides post directly to the site, it is not required to be proofread or go through an editor first (even though I usually have friends proofread for me).
It is prudent to check your website for any errors and encourage content creators to have someone proofread content or at the least use spell-checking. With spell check built into many programs (browsers, cms, and blogging software) it is simple as clicking a button. Just remember that some misspellings will not be caught by spell checking so keep an eye out for: their / they're / there, witch / which, weather / whether, too / to / two.