Pligg is a spam collector. I would never spend half of my life pruning weird contents.
There is a nice extension for RSS feeds at
www.ijoomla.com
: it allows your visitors to subscribe one or more RSS feeds from your site. Each section and category generates an RSS feeder that your subscribers can easily add to their RSS reader or to their site. They get free fresh content and you get free exposure and incoming links that increase your site popularity.
Thought you might be interested, not joomla but a whole new (beta) open-source web application called
Sweetcron
I am playing around at the moment. You might want to have a look, you basically add feed in the back end and/or add new post to be shown in the front-end. You have the control to unpublish items in feeds that you don't like.
It is a lifestream application but a potential news aggregator.