Fresh content is a distinct advantage for your search engine placement and for your site visitors. Repeat traffic from people and search engine spiders will increase proportionate to how fresh your content is. Producing fresh content takes time and resources. Tools like RSS Mix can help by automating a part of your content development.
RSS Mix allows you to combine any number of RSS feeds into one unique new feed. You can then use a parser to display a mix of stories from various sources on your website.