An aggregator or news aggregator is client software that uses a web feed to retrieve syndicated web content such as weblogs, podcasts, vlogs, and mainstream mass media websites.
One of the tasks i've been given is to differentiate between Blogs and RSS readers. To create something for the average joe to twig on easily. RSS readers really just to the dirty work for you, going out, checking your favourite sites to see if there are any new articles, and then organizes your news, making it easy and quick to read and scan. I've run through a few different readers, part of me uses Google's Custom Page reader, and the other part of me uses NetVibes, which offers some neat widgets that can also help you waste time ;-)
Readers can either be web based, or actual clients that you can download. I'm all for the web based ones, as I am usually working off 3 computers at a time, and it's simply handly to have it available, wherever I am.
Most of the readers are free, but I've also come across some that are subscription based, especially those for mobile devices. There are a few for the Blackberry, and some that aren't tied to specific devices. Mark Evans recommends Virtual Reach for mobiule devices, and you get a 7 day free trial ;-)
Pulling from Wikipedia:
Aggregators, or RSS Readers, reduce the time and effort needed to regularly checkwebsites for updates, creating a unique information space or "personalnewspaper." Once subscribed to a feed, an aggregator is able to checkfor 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 being built into portal sites such as My Yahoo! and Google; modern web browsers; e-mail programs like Mozilla Thunderbird; Apple's iTunes, which serves as a podcast aggregator and other applications. Devices such as mobile phones or Tivo video recorders (already aggregating television programs) may incorporate XML aggregators.
The aggregator provides a consolidated view of the content in asingle browser display or desktop application. Such applications arealso referred to as RSS readers, feed readers, feed aggregators or news readers.