Parsers extract articles from websites, then convert articles to a common format. This common format declares it is a list of information or a detail of "one" information.
A reader executes the parser and consumes the common format information. It displays the information if it is a detail. And execute the parser again if it is a list, when user has chosen to read a specific item in list.
There are information on the web which we like to read.
But they are not freely available.
We need to pay for them, such as by watching advertising flash animations, or popping out advertisement boxes when moving mouse pointer above an article.
We all understand the need of ads and appreciate the effort of authors.
But it gets annoying when seeing ads in mobile devices, which have limited bandwidth and computation power.
So website owners write apps for specific devices, serving their respective website information.
Finally, we have downloaded a dozen of apps, just for reading our favorite information. Then we just keep on opening apps and killing apps when reading from different information sources.
Some websites provide their information in RSS freely available format. No ads but it only contains the first or two sentences of the whole article. We can live with it, until we click on the "read more" button. It launches a browser and shows the website which provides the information, with ads of cause. Nextgen Reader is the leader doing this job. Well done.
So we have deleted some apps from our devices. Leaving those websites apps which do not provide RSS.
No worries authors. We still visits your sites and browses your ads, when we want to read your pics and videos posted in your sites.