Works in IE and FF. Buggy in Safari. Does not work in Opera. Ref: http://www.quirksmode.org/oddsandends/wbr.html

C'mon, any upvote for wbr should be more than equaled by downvotes for saying label is rare and/or obscure.

There is also the "Zero Width Break" character ​

You could inject it every x characters in very long words when parsing user input.

It is used in Thai where word breaks are not visible and line breaks are only allowed at word breaks.

Don't use <wbr>, use &shy; (soft hyphen). Actually renders with a hyphen attached, letting you know you're reading one broken word, and not just two odd ones (I'm sure this happens, but I can't think of a good example.)

wbr is not part of any standard.