Many apologies: due to a DNS issue, the demo of the Portuguese Wikipedia will be up only later today or tomorrow.  The demo on it.wikipedia.org is up now.
We are also looking forward to add some new large Wikipedia in the next days...
We have a semi-automated process for bringing such demos up.
I hope you find them useful! (and help us getting this done on the WMF, where it would work much better :-).
Luca

On Sat, Oct 17, 2009 at 4:14 PM, Luca de Alfaro <luca@dealfaro.org> wrote:
Dear All,

we finally managed to put up some demos of WikiTrust on some Wikipedias, to start gathering feedback.
WikiTrust (http://wikitrust.soe.ucsc.edu/) is an open-source tool that computes, for every word of text:
For the latter, we color in orange the background of untrusted text; the shade of orange gradually turns to white for text of increasing trust values. 

To see the demos, go to https://addons.mozilla.org/en-US/firefox/addon/11087 and install for Firefox the WikiTrust add-on.   You can then browse the Italian (it.wikimedia.org) and Portuguese (pt.wikimedia.org) Wikipedias, and we are working on adding other Wikipedias to the demo soon.

Some notes on the demo:

We developed the demo to help us test code suited to running at the Wikimedia Foundation (WMF).  But the code does not run there now: the demo is implemented by polling our servers at UC Santa Cruz to obtain the text information.  This has a few consequences:
The purpose of the demo is to help us test the code and experiment, and feedback is most welcome.  Please be tolerant: I am sure there are still kinks, and we will do our best to iron them out.  You can find links to mailing lists, bug-tracking systems, code, etc at http://wikitrust.soe.ucsc.edu/

Some notes on text trust:

Text trust is computed on the basis of a reputation system for Wikipedia users.   Users gain reputation when they make contributions that last in the system.  Thus, new users must do some amount of good work before they gain reputation.  The trust of the text then depends on the reputation of the user who inserted the text, and on the reputation of all the users who subsequently revised the text.  Text can become fully trusted only when it has been revised by multiple high-reputation authors.  Thus, WikiTrust highlights changes in articles, and makes it difficult for authors of malicious changes to cover their tracks.

If you click on a word of text, you are sent to the revision where the word was inserted.  We also can have pop-up balloons that announce the author of each word, but we thought that this too-obvious proclamation of who the author is could lead to silly competition for who last replaced or reworded a sentence.
We also had the option of voting for the validity of a revision, thus raising its trust, but since our code does not run at the Wikimedia Foundation (WMF), we have no way of authenticating votes, and this feature is thus currently inactive.

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I hope you enjoy the demo, and I hope this can be a useful instrument for those who patrol, maintain, and improve Wikipedia pages, as well as for those who are just visitors.

All the best,

Luca, Bo, and Ian