Web Design & Development Guide
In computing, a feed aggregator, also known as a feed reader
or simply as an aggregator, is
client software or a
Web application which aggregates
syndicated web content such as news headlines, blogs,
vlogs in a
single location for easy viewing.
Aggregators reduce the time and effort needed to regularly check websites for
updates, creating a unique information space or "personal newspaper." Once
subscribed to a feed, an aggregator is able to check for new content at
user-determined intervals and retrieve the update. The content is sometimes
described as being "pulled" to the subscriber, as opposed to "pushed" with email
or IM. Unlike recipients of some "pushed" information, the aggregator user can
easily unsubscribe from a feed.
Aggregator features are frequently built into portal sites (such as My Yahoo!
and iGoogle), modern Web browsers and email programs.
The aggregator provides a consolidated view of the content in a single
browser display or desktop application. Such applications are also referred to
as RSS readers,
feed readers, feed aggregators, news readers or
search aggregators. Aggregators with podcasting capabilites can
automatically download media files, such as MP3 recordings. In some cases, these
can be automatically loaded onto portable media players (like iPods) when they
are connected to the PC.
Recently, so-called RSS-narrators have appeared, which not only
aggregate text-only news feeds, but also convert them into audio recordings for
The syndicated content an aggregator will retrieve and interpret is usually
supplied in the form of
RSS or other XML-formatted data, such as RDF/XML or
The variety of software applications and components that are available to
collect, format, translate, and republish XML feeds is a testament to the
flexibility of the format and has shown the usefulness of
Web based aggregators are applications that reside on remote servers and are
typically available as
Web applications such as
Google Reader or Bloglines. Because the application is available via the Web, it can be
accessed anywhere by a user with an Internet connection.
More advanced methods of aggregating feeds are provided via
AJAX coding techniques and
XML components known as Web widgets. Ranging from full-fledged applications to
small fragments of code that can be integrated into larger programs, they allow
users to aggregate OPML files, email services, documents, or feeds into a single
interface. Many customizable homepage/portal implementations such as iGoogle,
Live.com, My Yahoo!, and Pageflakes provide such functionality.
In addition to personal aggregators, planet sites are used by online
communities to aggregate community blogs in a centralised location. Such sites
are named after the
Planet aggregator, an application designed for this purpose.
Client software aggregators are installed applications designed to collect
Web feed subscriptions and group them together using a user-friendly interface.
graphical user interface of such applications often closely resembles that of
popular e-mail clients, using a three-panel composition in which subscriptions are
grouped in a frame on the left, and individual entries are browsed, selected,
and read in a frames on the right.
Software aggregators can also take the form of news tickers which scroll
feeds like ticker tape, alerters that display updates in windows as they are
refreshed, or as smaller components (sometimes called plugins or extensions),
which can integrate feeds into the Operating System or software applications
such as a Web browser.
Media aggregators are sometimes referred to as "Podcatchers" due to the
popularity of the term "podcast"
used to refer to a web feed containing audio or video. Media aggregators refer
to applications, client software or Web based, which maintain subscriptions to
feeds that contain audio or video
media enclosures. They can be used to automatically download media, playback
the media within the application interface, or synchronize media content with a
portable media player.
One of the problems with news aggregators is that the volume of articles can
sometimes be overwhelming, especially when the user has many Web feed
subscriptions. As a solution, many feed readers allow users to
tag each feed with one or more keywords which can be used to sort and
filter the available articles into easily navigable categories.
Web syndication formats