  Wikidata has grown to a knowledge graph with an impressive size. To date, it
contains more than 17 billion triples collecting information about people,
places, films, stars, publications, proteins, and many more. On the other side,
most of the information on the Web is not published in highly structured data
repositories like Wikidata, but rather as unstructured and semi-structured
content, more concretely in HTML pages containing text and tables. Finding,
monitoring, and organizing this data in a knowledge graph is requiring
considerable work from human editors. The volume and complexity of the data
make this task difficult and time-consuming. In this work, we present a
framework that is able to identify and extract new facts that are published
under multiple Web domains so that they can be proposed for validation by
Wikidata editors. The framework is relying on question-answering technologies.
We take inspiration from ideas that are used to extract facts from textual
collections and adapt them to extract facts from Web pages. For achieving this,
we demonstrate that language models can be adapted to extract facts not only
from textual collections but also from Web pages. By exploiting the information
already contained in Wikidata the proposed framework can be trained without the
need for any additional learning signals and can extract new facts for a wide
range of properties and domains. Following this path, Wikidata can be used as a
seed to extract facts on the Web. Our experiments show that we can achieve a
mean performance of 84.07 at F1-score. Moreover, our estimations show that we
can potentially extract millions of facts that can be proposed for human
validation. The goal is to help editors in their daily tasks and contribute to
the completion of the Wikidata knowledge graph.
