It pulls articles from RSS feeds. RSS is a xml format primarily used for syndicating news. Many news related sites provide RSS files of their recently posted articles so their readers can use an RSS aggregator (e.g.
http://www.sharpreader.net) to read the data.
With PHP's XML libraries, parsing RSS is done very easily.
Sample RSS:
http://rss.news.yahoo.com/rss/topstories
Anyhow, you first create an article bot, by assigning it a user it will control.
You add an RSS feed by specifying the path to the RSS file, the article bot it applies to, the forum the thread will be posted in, and an interval (in minutes) that a new thread will be posted.
It's preferred that you use a crontab to execute the articlebot.php file, every couple hours or so. The script will work from the bottom of the RSS file (oldest articles) to the top (latest articles). It will post the title of the article as the thread subject, and then the RSS description as the body content. It then tags the URL to the actual full article.
I've had it running on my forum for about 2 weeks, and it works quite well. Make the intervals quite large, like every 5 hours, or else you'll have a flood of bot threads on your forum.

This of course depends on the RSS feed and how often the news source updates it.
Hopefully I didn't make things more convoluted.