Re: defining mediator

ping@lfw.org writes:
 > > - HyperNews, Slashdot, PageSeeder, the mediator is on the (remote) server
 > > which has the mark document and the related annotations. Call it
 > > "integrated" ??
 > 
 > These things also aren't mediators, for the opposite reason:
 > there is no web page that they are taking as input to produce
 > the result.  That is, you can't use HyperNews or Slashdot to mark
 > up an arbitrary public website, for example.  

I don't know about the others (I haven't been keeping up) but HyperNews
allows you to reference an arbitrary public website which is used as the
"base article" for a forum.  As an example, see:
http://www.hypernews.org/HyperNews/get/w3c.html. The reference to
http://www.w3.org/ is invisible, but it could easily be made visible.
The ability to set up such forums is restricted, but it could easily be
opened up to allow anyone to create forums, if you want to deal with the
administrative and server scaling problems that might cause.  Instead, I
had hoped people would install their own copies of HyperNews, and that
has worked reasonably well.  Most people just want the forum features
regardless what is at the top of the forum.

This feature was also turned into a general annotation service usable by
certain limited versions of Mosaic and HotJava, where the annotations
can be sent to the browser without necessarily marking up the page being
annotated.  

HyperNews does not support any embedded or "invasive" annotations - I
looked into doing that, but there are many user interface issues I
didn't have time to fully consider.  CritLink does a good job in this
area.

 > A mediator is a real-time converter: it takes a web page as input
 > and produces a web page as output.  (Strictly speaking, a mediator
 > can and should, for performance reasons, work on an input *stream*
 > which it incrementally parses, and produce an output stream.)

HyperNews does that, but it is easy if you don't have to embed
annotations.  Another optimization (supported by HyperNews) is to make
use of a cache of the pages being annotated.

-- 
Daniel LaLiberte
liberte@w3.org

Received on Tuesday, 14 September 1999 13:35:08 UTC