If you are concerned that your Plone site will grow up to be a fatty, you need to seriously consider upfront.diet. upfront.diet is a collection of fat burning code snippets and disciplines that will keep your Plone site fit and in shape. If you want to write Plone apps that need to scale to millions of objects, you'll need a fundamental understanding of what is inside each pickle in the ZODB. This talk will go over the fundamentals and explore the tools that abstract it right away so that you can forget about it, and focus on development.
Clipping is a handy way to collect important slides you want to go back to later.