  Entity linking is the task of identifying mentions of entities in text, and
linking them to entries in a knowledge base. This task is especially difficult
in microblogs, as there is little additional text to provide disambiguating
context; rather, authors rely on an implicit common ground of shared knowledge
with their readers. In this paper, we attempt to capture some of this implicit
context by exploiting the social network structure in microblogs. We build on
the theory of homophily, which implies that socially linked individuals share
interests, and are therefore likely to mention the same sorts of entities. We
implement this idea by encoding authors, mentions, and entities in a continuous
vector space, which is constructed so that socially-connected authors have
similar vector representations. These vectors are incorporated into a neural
structured prediction model, which captures structural constraints that are
inherent in the entity linking task. Together, these design decisions yield F1
improvements of 1%-5% on benchmark datasets, as compared to the previous
state-of-the-art.
