Z:gnu-www-ja-software-patents--1b6f25-That means don't use the idea/en

That means don't use the idea that the patent covers. This can be easy or hard, depending on what that idea is. In some cases, a feature is patented. Then you avoid the patent by not implementing that feature. Then it just matters how important is that feature. In some cases, you can live without it. A while ago, the users of the word processor XyWrite got a downgrade in the mail. The downgrade removed a feature which allowed you to pre-define abbreviations. That when you typed an abbreviation followed by a punctuation character, it would immediately replace itself with by some expansion.