Microsoft have just announced a significant update to Project Online, now allowing for up to 30,000 projects to be stored. This is a massive increase from the previous published limit of 5000 projects. Better still, every one of those project can have its own project site. This is clearly a great piece of innovation, and the result of Microsoft investing much of its R&D budget for the product into performance and scalability improvement.
You can find the full detail of this announcement here.