RSS and Podcast Feeds
RSS or Really Simple Syndication is a standardised format for delivering and receiving news type information. (See the BBC News Feed below).
If you wish your site to be really informative on a particular issue or subject, without having to produce all the content yourself, it might be worth considering implementing an RSS feed from elsewhere, which could deliver regular updated news and information.
Alternatively, you may decide that want to broadcast new and updated information regularly yourself. In which case you might want to invite visitors to subscribe to your own RSS feed.
Podcasts are essentially similar to RSS Feeds, but take the form of syndicated audio or video information. These too can be included on your site.