There are millions (if not billions) of lines of VB6 code out there. For many businesses, they need this code moved to .NET but they can't just throw the baby out with the bathwater and start from scratch.
They might not be able to afford this, or maybe they couldn't rebuild it if they tried. It is amazing how many business rules are embedded in systems over time, and people forget how the real rules work. Porting software many times doesn’t work, you just end up with an old system on a new platform, lots of technical debt, and a maintenance nightmare.
This is where a tool assisted rewrite comes in. Mark Juras (from Great Migrations) and Brian H. Prince will talk about how special tools, and an iterative process can help you quickly rewrite your code from VB6 to .NET, keeping all of the business rules intact, without losing those precious business rules. The new system can mirror whatever target architecture you would like to move to.