APIs / feeds
Valuable, professional content can be added to websites using APIs or RSS feeds (for example).
Using PHP, these feeds can be integrated seamlessly into a website, assuming the URL of the destination website, as if the content were its own.
Example
The NHS provide high quality medical information via an API:
Here's a site that use the NHS API:
Example content supplier
- Coming soon, check the forum!
Content is not original
This type of content is clearly not unique to your website. Therefore it has limited SEO benefits, as pages with duplicate content is usually removed from search engine results. However, it certainly adds value to your visitors.
Also worth noting that control over your own content is lost. e.g. host server failure, connection problems, inappropriate content.