Soft breaks in HTML text
If you want to hint to the web browser where to break a word when it doesn't fit on the same line there's a nice little thing called soft hyphen, available through ­ (also ­ or ­).
<p>This is an example of a wordthat­shouldbreak in the middle if it doesn't fit on the same line.</p>
The above example will break the made up "wordthatshouldbreak" at the ­ character if the whole word doesn't fit on the same line, resulting in "wordthat-shouldbreak".
More info about line breaks and hyphenation over at W3's HTML 4.01 Specification.