  When a user views an archived page using the archive's user interface (UI),
the user selects a datetime to view from a list. The archived web page, if
available, is then displayed. From this display, the web archive UI attempts to
simulate the web browsing experience by smoothly transitioning between archived
pages. During this process, the target datetime changes with each link
followed; drifting away from the datetime originally selected. When browsing
sparsely-archived pages, this nearly-silent drift can be many years in just a
few clicks. We conducted 200,000 acyclic walks of archived pages, following up
to 50 links per walk, comparing the results of two target datetime policies.
The Sliding Target policy allows the target datetime to change as it does in
archive UIs such as the Internet Archive's Wayback Machine. The Sticky Target
policy, represented by the Memento API, keeps the target datetime the same
throughout the walk. We found that the Sliding Target policy drift increases
with the number of walk steps, number of domains visited, and choice (number of
links available). However, the Sticky Target policy controls temporal drift,
holding it to less than 30 days on average regardless of walk length or number
of domains visited. The Sticky Target policy shows some increase as choice
increases, but this may be caused by other factors. We conclude that based on
walk length, the Sticky Target policy generally produces at least 30 days less
drift than the Sliding Target policy.
