Some mod_rewrite implementations (particularly in Apache 1.3) make regular expressions greedy by default. These same implementations usually don’t support the reluctant modifier (‘?’) either. This presents a problem for permalink structures that use the %category% tag since the regular expression for this tag gobbles up characters when run in greedy (non-reluctant) mode. The Ungreedy Rewrite Plugin works around this by using an alternative regular expression for %category% that employs a limited, non-greedy character set. The drawback to this is that i18n URIs are not supported. If your blog is non-English, these rules may not work for you.