Some actions that happen between online material and a user can be initiated in one of two ways. Others are initiated in one way only. The initiation methods are referred to as push technology and pull technology. Push technology involves data being automatically delivered to the computer of the user, either on a schedule or based on some triggering event. Pull technology is the opposite: it involves a specific user request to move the data to the user’s computer. There are four frequent uses of pull technology: requesting mail, loading webpages, downloading from the Internet, and web syndication to a newsreader.
Email clients can work with either push technology or pull technology, but this depends on the client, rather than the user’s choice. If a client offering pull technology is being used, the client will be offered preference settings that will allow him or her to configure the email client to periodically poll the server and download the email. Once this step is taken, the downloading happens automatically, so this pull technology can feel like push technology. Nevertheless, the user maintains control and can change the polling interval, or even turn off the client, if desired.
On the Internet, every entry of a URL or click on a page link that results in a loaded webpage is the result of pull technology at work, although many people think of it primarily as “navigation.” It is clearer that something is being pulled when a user downloads some item from the Internet. This is the case whether when downloads a webpage to one’s printer, an ebook purchase from Amazon®, a new driver for one’s monitor, a photograph from Flickr®, a catalog of English Language Teaching titles from Oxford University Press Canada®, or webmail that one goes on line to retrieve oneself.
Web syndication allows users to gather updates from chosen websites and read them offline through a newsreader on their desktop, such as NetNewsWire®, if they choose. When they do this — rather than read them through a browser such as Bloglines®, which keeps them online — they are taking advantage of pull technology in a different way. The material of their choice will be delivered to them as it becomes available, but only because they made the request for it in the first place and only when they launch the program. Keep it off, and nothing is pulled.