Aggregators

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, 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 capabilities 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 end-user's computer.

Recently, so-called RSS-narrators have appeared, which not only aggregate text-only news feeds, but also convert them into audio recordings for offline listening.

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 Atom.

For example, if there are many sites you visit frequently, without RSS the only way you can find out if anything on the sites has been updated is to go to each site individually. This can take a long time. RSS is an information aggregation technology that helps you to integrate these websites in one browser or page that can show the new or updated information from all the sites you choose, regardless of whether the content is text, music, pictures, or video. Customers only need to find an RSS feed on the internet and add that in their RSS reader. There are many successful on-line RSS Readers, such as My Yahoo! and Google Reader. There is also a variety of RSS software: Feed Demon, and RSS Reader for example. For network security, users can choose what items can be shown in their RSS readers, like title, author or others, so it can exclude spam.

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 presentation-independent data.

The most commonly known web-based aggregators are reader applications on the web. These are meant for personal use and are hosted on remote servers. 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 and portal implementations provide such functionality.

In addition to aggregator services mainly for individual use, there are web applications that can be used to aggregate several blogs into one. One such variety—called planet sites—are used by online communities to aggregate community blogs in a centralized location. They are named after the Planet aggregator, a server 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. The 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 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, web browser macro tools 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.