Perhaps you have seen various icons like this around the Internet. RSS stands for "Really Simple Syndication". As its name implies, it is designed to syndicate content without having to go to the website containing the content. RSS allows users to gather lots of information without visiting each and every website. This saves time, effort, and bandwidth.
To use RSS, you need something called a RSS "feed reader". RSS is just a plain old XML document containing information. A feed reader knows how to "consume" the RSS feed data into a more human-readable format. Popular web browsers (e.g. Firefox) and e-mail clients have RSS feed capabilities built into them. However, there are also dedicated solutions.
MyProBB supports RSS feeds. This means you can read the latest forum posts from inside your favorite feed reader.