What is an RSS feed?
RSS stands for Really Simple Syndication. An RSS feed is a format that is used to publish a website's data. It is most commonly used for websites that are frequently updated, like blogs, news sites, or podcasts. An RSS feed allows websurfers to subscribe these websites so that they are automatically updated whenever new content is published on that site. It is sort of like taking a subscription to a magazine and having it delivered to your house instead of having to go to the newsagent to buy it. In this case, a summary or full post is sent to your email or a feedreader where you can read it without having to go to the website. RSS feeds make it easier to keep track of updates to many blogs and websites without having to physically visit each website.
How do you use a feed?
There are various "feed readers" available that allow you to collect the feeds of all your favourite websites. For instance, Technorati and Bloglines are just two of the many feed readers available online. To find others, just google "feed readers". Personally, I prefer the layout of Bloglines, but to each his own.
Once you register for an account with a feed reader, you can enter the url of the blog or the feed of the blog's url that you want to be kept updated on. The feed reader will then check the blogs that you are subscribed to on a regular basis and notify you of any new updates through a method that operates fairly similarly to new messages in your email inbox. The benefit of this is that you can monitor various blogs without the pain of individually going to each url to check if there have been any new updates since you last visited. If you still want to look at the site, you can click on the links supplied by your feed reader.
Setting Up Your Own Feed Subscription
Some free website designs already have an RSS button that allows your readers to get your feed easily. If you don't have that, you can set one up for your own blog or website by using Feedburner. Just sign up for a free account and follow the instructions to set-up your feed. Once you have your feed url, you can get a snippet of code to add to your blog and it will appear as an RSS button that your readers can use to subscribe to your blog.
Email Subscriptions
You can also choose to have an email subscription instead of a RSS feed subscription. An email subscription allows a reader to subscribe to a blog and get new posts for that blog delivered to straight to their inbox so they don't have to sign up for a feedreader account.
If you want to set up an email subscription facility for your blog, you can also use Feedburner. There are also other services that provide email subscription services that you can add to your blog, like Feedblitz. Personally, I prefer Feedburner because it has some other pretty cool features.