add_duration            Add time spent in seconds on webpage
add_panelist_data       Add panelist features to webtrack data Add
                        characteristics of panelists (e.g. from a
                        survey) to the webtrack data
aggregate_duration      Aggregate duration of consecutive visits to a
                        website
audience_incidence      Create incidence matrix for audience-outlet
                        network
audience_network        Create audience networks
bakshy                  Bakshy Top500 Ideological alignment of 500
                        domains based on facebook data
classify_domains        Classify domains according to prespecified
                        classes
create_urldummy         Create an urldummy variable from a data.table
                        object
domain_list             Domain list classification of domains into
                        news,portals, search, and social media
extract_domain          Extract domain from url
isolation_index         Isolation Index In terms of news exposure, the
                        isolation index captures the extent to which
                        conservatives disproportionately visit outlets
                        whose other visitors are conservative
news_types              News Types
print.wt_dt             Print web tracking data
summary.wt_dt           Summary function for webtrack data
test_data               Test data
test_survey             Test survey
vars_exist              Check if columns are present
wt_dt                   An S3 class, based on data.table, to store
                        webtrack data
