Some things to think about if you're planning on providing a more secure Plone site. While Plone is a very secure CMS with an incredible track record, there are still plenty of things you can do to protect sites that might be larger targets.
This will show you how to make a traversable multi-adapter on the context and request object that can be called within tal expressions and used as utilities elsewhere. It is done the exact same way as the plone_tools, plone_context_state, plone_portal_state BrowserViews you see used often throughout Plone viewlets and tal expressions.
Browser layers are used to specify views and resources and are only specific to your plone site. It is much like what a theme does, you just don't need to select the theme in the site settings. It works on a per site basis and is only enabled when your product is installed.
This shows how you can add new columns/fields to sort by and retrieve in your smart folders for new content types. This is useful if you have custom content types that you want to still use smart folders with.