In this section we explore incentives to induce cooperation.
In a P2P system it is important for users to voluntarily coop-
erate. In P2P Wikipedia maximal cooperation is essential,
because the success of tagging depends on their quantity.
Voluntary cooperation does occur in the online world, but
we believe we can stimulate more users to cooperate. By
using the right incentives we hope to induce users to coop-
erate and explore the ‘tagged universe’. Furthermore, the
user interface has to be an attractive representation of and
supporting the ideas about inducing human cooperation.
Incentives to cooperate Social psychologists identify
two basic motivational forces [14] for cooperative behavior.
First, instrumental, or environmentally driven motivation:
people either see the chance of a reward if they cooperate,
or fear punishment if they do not cooperate. For instance,
websites like (amazon.com) reward their users with badges
that show their status and higher ranks in top-n lists. Sec-
ond, internally driven motivation: the influence of personal
values in the form of obligation to the group and its rules
(legitimacy), and of attitudes relevant to the group (com-
mitment, satisfaction, feelings toward group authorities, and
loyalty). The latter is also known as ingroup identification
[12]. How people behave within their group (or virtual com-
munity) is also influenced by their wish to create a positive
public self. Factors that influence the way people present
themselves positively include the willingness to cooperate,
the feeling of belonging, competitiveness, the need to dis-
tinct oneself from others, the possibility to convince others
of ones opinion or taste.
Personalized navigation Tag-based navigation can be
an additional way to explore Wikipedia, especially for video
files. A user’s taste is learned from creating new content,
tagging, moderating, searching, and browsing. The Bud-
dycast algorithm then calculates the user’s taste buddies -
also known as tag buddies in P2P Wikipedia - to create a
sense of belonging to a community. From all this it will also
be easier to calculate recommendations, as is done in the
Tribler system, and tag-to-tag similarity. They both result
in a much richer and more serendipitous exploration of the
‘tagged universe’.
The main navigation screen in Figure 3 shows the calcu-
lated tag cloud with 50 - 100 top Wikipedia tags on the
left, arranged alphabetically. Their relative ranking is ex-
pressed in font-size. The means of navigation in this proto-
type are keyword searching with one or two keywords, and
tag-browsing. The area on the right is used for personalized
settings, containing:
a) My Tags. Summarizing the user’s most often used
tags. Like the tag cloud on the left, this personal tag cloud
is arranged alphabetically, and the ranking is expressed in
font-size.
b) Recent Tags. A list of most recently viewed tags (x