Are RSS-Feeds only a link directory or should the items be posted to the target?

Hi. I am trying to setup the RSS feed option in a page. Unfortunately the link is only shown to the users but not the items of the feed. Should'nt new entries be posted in the group automatically? The cron has no option about it. It looks to me like this is only a link directory which is kind of useless. Whats the idea behind this? Or if it should work as I expect it.. how can I trigger the creation of post items?