[nene]

3. For a limited time? 20 years is pretty much forever in the software industry. So sure you might start to look at alternative ways, but it can be quite hard when the obvious solution is patented. But often the patent attempts to cover the most general idea possible, so your entirely different implementation of the idea might still be infringing the patent.

But the main problem with software patents in particular is that you can never be sure if you're infringing something. You can only hope that you don't.