  Limited search and access patterns over Web archives have been well
documented. One of the key reasons is the lack of understanding of the user
access patterns over such collections, which in turn is attributed to the lack
of effective search interfaces. Current search interfaces for Web archives are
(a) either purely navigational or (b) have sub-optimal search experience due to
ineffective retrieval models or query modeling. We identify that external
longitudinal resources, such as social bookmarking data, are crucial sources to
identify important and popular websites in the past. To this extent we present
Tempas, a tag-based temporal search engine for Web archives.
  Websites are posted at specific times of interest on several external
platforms, such as bookmarking sites like Delicious. Attached tags not only act
as relevant descriptors useful for retrieval, but also encode the time of
relevance. With Tempas we tackle the challenge of temporally searching a Web
archive by indexing tags and time. We allow temporal selections for search
terms, rank documents based on their popularity and also provide meaningful
query recommendations by exploiting tag-tag and tag-document co-occurrence
statistics in arbitrary time windows. Finally, Tempas operates as a fairly
non-invasive indexing framework. By not dealing with contents from the actual
Web archive it constitutes an attractive and low-overhead approach for quick
access into Web archives.
