Years ago dynamic websites posed significant problems for search engines. While the engines have come a long way since the early days of dynamic website development, there are still some key problems that arise. Google has gone public stating that you don’t need to fix your dynamic site problems, but in reality that’s poor advice for the website owner.
Google says this in their own self interests so they can use your problems to fix theirs. But when engaging in the battle of online visibility, you don’t want to sit around while Google figures out how to plug the holes with their indexing spiders. You need to be proactive and fix the issues so you can be competitive today, not tomorrow.