Subscriptions, or feeds as they are commonly called, are simple ways for web publishers (bloggers, podcasters, news sites, etc.) to notify interested individuals when the publisher's online content changes. Subscriptions or feeds save you time by not having to continually check a Web site to see if there is anything new. Instead, an short message, headline, summary, or alert is sent to every subscriber indicating there is something new to view on each selected site.
Interested individuals subscribe to feeds, through a feed aggregators, which give them access to all desired subscriptions in one location. Many feed aggregators are available. Some are standalome applications, others are add-in utilities to Outlook or your Web browser. Some feed aggregators are free while others require payment.
I use a feed aggregator called Sage as an add-in extension to Mozilla Firefox, my browser. Both Sage and Firefox are products of the Open Source software developement community and are available at no charge.
When I visit a Web site, like www.ahlsmith.com, and I want to automatically know when something new is added to that site, I click on the Discover Feeds icon on the Sage sidebar and if the site supports RSS or Atom feeds (the most commons types of subscription feeds), Sage automatically reads the feeds and regesters a subscription.
When I have time to see what's new among the sites that interest me, I simply click on the Check Feeds icon on the Sage sidebar and check the Update icon next to each subscribed site to see if new or changed content exists. If it does, I click on the site's icon to read a summary of of the new content. If I want more information, I click-through the summary and go directly to the site. All the time, the Sage sidebar stay visible along the left side of my Firefox browser window.