In general this is a very risky strategy for a community since (if automated from some external news source) you are basically spamming your forum with auto-generated topics. This will quickly inundate your site with low value topics that have no replies.
The organic community based way to do this is either:
- Curate the news and post topics based on what you (or a core of power users / editors) think is interesting, whole sites are based on this strategy such as Boing Boing.
or
- Have an active community that already posts topics, and wait for the community to post topics about interesting news events themselves, or otherwise encourage them to do so