title: Why use multibyte string functions in PHP?
body: <p>At the moment, I don't understand <strong>why</strong> it is really important to use mbstring functions in PHP when dealing with UTF-8? My locale under linux is already set to UTF-8, so why doesn't functions like <code>strlen</code>, <code>preg_replace</code> and so on don't work properly by default?</p>