(or most often 
)
it should link to an RSS feed that you can subscribe to via your RSS client.
What Is RSS?
RSS (Really Simple Syndication) provides a convienent way to syndicate information from a variety of sources, including news stories, updates to a web site or even source code check-ins for a development project. Regardless of the purpose for which the RSS file is being used, by watching this XML file, you can quickly and easily see whenever an update has occurred. Of course, viewing the RSS feed in Internet Explorer or Firefox and checking repeatedly for news is not the most efficient use of your time, so most people take advantage of some form of client software to read and monitor RSS feeds (aggregator). In fact, one can subscribe to a RSS, and then the client installed on his/her machine will automatically get new items from each of the feeds.
There are many different RSS clients available, some are free, but here are few that you may find useful:
In practical terms, to subscribe to the "Tools for Agro-Ecological Modeling" RSS feed one must install one aggregator on the local machine, then use the address of the RSS page to subscribe. Very quick, very efficent.
Whenever
you see this
(or most often )
it should link to an RSS feed that you can subscribe to via your RSS client.