RSS is technology - a simple software program - that allows you to access web and blog content automatically. The acronym's most popular translation is "Really Simple Syndication. Once your browser or computer has an RSS reader on board, you can subscribe to any number of RSS "feeds." A feed is simply a way in which a reader may subscribe to website content - most commonly blogs or news sites. A news site, for example, may list their latest headlines or entire articles in their feed every time a new article is published. A blog would publish this feed as a series of recent posts.
Feeds are published by millions of publishers, from small individuals to large organizations like Newsweek. The value of a feed is that it brings the most current site content to you in a format that is easily scanned; further, you are spared the task of visiting each source site each day. This is typically done through the use of what is called an 'aggregator' or 'feed reader'.
Feed readers or RSS readers, are software programs that run on your computer (or PDA or phone); let you easily subscribe to feeds, and allow you to read through them efficiently. Some are relatively simple, showing the headline and summary. The fancier ones often work with (or in) your browser to make viewing the material look much like the source page. Once you have a reader on your computer, subscribing to a feed with is an easy click or drag from your browser. Sites that provide RSS feeds will usually have a button for that purpose.
There are several RSS feed formats as well as one with an entirely different methodology called Atom. Atom has become popular with some bloggers and blogging tools. Some aggregators can read both. The other acronyms you will see in "feedspeak" are XML, which stands for 'extensible markup language' and is the code standard for these simple text feeds. An 'OPML" file is a format for indexing hierarchical feed lists. If you dive into this web habit in a big way, your aggregator or reader may keep your subscription list in an OPML file.
An RSS feed is a great method for staying abreast of issues and topics that interest you. There are a number of feed "libraries," so to speak, from which you can learn what's out there in your areas of interest. Google has a built-in reader that makes the subscription process easy, as does Yahoo. Firefox has a downloadable extension for the purpose of aggregating RSS feeds, as well as a default ability to save RSS feeds as "live bookmarks" that update via the RSS feed. You can download a number of stand alone readers and aggregators; you can find them through a simple web search.
The whole RSS "movement" is a step towards utilizing the Internet more efficiently. The trick is to avoid overloading your email inbox with daily reports that you end up ignoring most of the time. For that purpose, there are sites like Feedster that will search millions of RSS feeds for articles that are relevant to your interests. Like any search tool, however, these services are hit and miss. They are still working off keywords and sometimes what they find is relevant, sometimes not. But if you want daily news broken into categories, it's great technology once you learn how to make it work for you.