We are exploring the use of these methods in routine Internet use from a site in India (a software development laboratory, multi-user LAN, connected to an Internet service provider through an expensive dial-up link) and from mobile computers (e.g., HP100LX and Gateway Handbook) in the US. In each case the user's Internet access is through a thin link, with a bandwidth somewhere between 2400 bps and 28.8 kbps.

Local caching and prefetching of resources naturally suggests itself as a useful candidate. It appears that transparent replay of application protocols is a practical way to retrofit resource caching into existing (shrinkwrapped) software. One promising method which works with most services of interest is Postel spoofing.

Given the “browsing” mode of network usage, progressive encoding mechanisms are shown to effectively reduce the access time for particularly large Internet objects, such as Web pages. An ideal progressive encoding of a resource sends a gross quality rendering followed by successive refinements. Since only a fraction of the images retrieved in a session actually have long-term value, such techniques can reduce on-line bandwidth demands by an order of magnitude. Obviously, such encoding methods apply also to large archive and distribution files (such as from FTP archives).

Filtering and relevance feedback have been recognised as effective tools in overcoming information overload. Many sophisticated general techniques are a subject of active research. However, we found that exploiting certain behaviour patterns typical in Internet usage permits particularly efficient filtering using surprisingly simple methods.

We apply this to USENET communication, and extend this to other services (FTP, HTTP, Gopher, mail, etc.), and outline a method of filtering network hypermedia on the basis of relevance contours. Our method recognises the amount of selected information that can be digested by a user in a day, and maximises the value of the packet so selected. It also differs from others by integrating all network hypermedia and selecting and filtering items without regard to the service they were accessed from (USENET, Web, Gopher, FTP, etc.). It does not depend on a-priori categorisation such as news groups and the consequent need for explicit subscription and unsubscription.