If you operate either a guestbook or a blog, you can either approve all posts manually, or you publish them straight away.  The least effort is to publish immediately, and set an email notification so you can monitor what's been posted.

However, it would also be sensible for website managers to have remote, mobile access to editing such comments; most of us arent at our computers all the time and an offensive or unwelcome post should be removed asap, even if we're on holiday, in the pub or travelling.