  Wikipedia relies on an extensive review process to verify that the content of
each individual page is unbiased and presents a neutral point of view. Less
attention has been paid to possible biases in the hyperlink structure of
Wikipedia, which has a significant influence on the user's exploration process
when visiting more than one page. The evaluation of hyperlink bias is
challenging because it depends on the global view rather than the text of
individual pages. In this paper, we focus on the influence of the interconnect
topology between articles describing complementary aspects of polarizing
topics. We introduce a novel measure of exposure to diverse information to
quantify users' exposure to different aspects of a topic throughout an entire
surfing session, rather than just one click ahead. We apply this measure to six
polarizing topics (e.g., gun control and gun right), and we identify cases in
which the network topology significantly limits the exposure of users to
diverse information on the topic, encouraging users to remain in a knowledge
bubble. Our findings demonstrate the importance of evaluating Wikipedia's
network structure in addition to the extensive review of individual articles.
