The principal cost-free paths to high search engine positioning are regular, relevant content updates and cross-linking with partner sites. The former is where many companies create a rod for their own backs. To this end we would normally suggest enrolling a group of people to keep smaller parts of the site up to date.
The system allows you to take direct control over security and access within the administration site and as such you can permission some contributors to create or edit content only in specific areas. You may also set them, or all, people such that any content the add goes through an editor before appearing on the site. This allows you to share the update responsibility but still retain overall control.
Alternatively, as the site could allow you to generate your own RSS feeds out to visitors, we can configure the system to automatically retrieve content from pre-determined locations. Again once retrieved this could be automatically published or sent to an editor for sign-off. This source could be a web-site and RSS news feed or simply data held on an accessible server. Clearly permission and copyright issues would need to be verified.