  In various domains and cases, we observe the creation and usage of
information elements which are unnamed. Such elements do not have a name, or
may have a name that is not externally referable (usually meaningless and not
persistent over time). This paper discusses why we will never `escape' from the
problem of having to construct mappings between such unnamed elements in
information systems. Since unnamed elements nowadays occur very often in the
framework of the Semantic Web and Linked Data as blank nodes, the paper
describes scenarios that can benefit from methods that compute mappings between
the unnamed elements. For each scenario, the corresponding bnode matching
problem is formally defined. Based on this analysis, we try to reach to more a
general formulation of the problem, which can be useful for guiding the
required technological advances. To this end, the paper finally discusses
methods to realize blank node matching, the implementations that exist, and
identifies open issues and challenges.
