  Query-based searching and browsing-based navigation are the two main
components of exploratory search. Search lets users dig in deep by controlling
their actions to focus on and find just the information they need, whereas
navigation helps them to get an overview to decide which content is most
important. In this paper, we introduce the concept of "search powered
navigation" and investigate the effect of empowering navigation with search
functionality on information seeking behavior of users and their experience by
conducting a user study on exploratory search tasks, differentiated by
different types of information needs. Our main findings are as follows: First,
we observe radically different search tactics. Using search, users are able to
control and augment their search focus, hence they explore the data in a
depth-first, bottom-up manner. Conversely, using pure navigation they tend to
check different options to be able to decide on their path into the data, which
corresponds to a breadth-first, top-down exploration. Second, we observe a
general natural tendency to combine aspects of search and navigation, however,
our experiments show that the search functionality is essential to solve
exploratory search tasks that require finding documents related to a narrow
domain. Third, we observe a natural need for search powered navigation: users
using a system without search functionality find creative ways to mimic
searching using navigation.
