Abstract—Semantic web service technologies have been
proposed to enable automatic web service discovery and
composition. But such approaches are suffered from significant
effort to construct domain ontologies and to annotate web
services with semantics by third parties. Hence social and
collaborative tagging systems have been gaining the popularity
on the web. Folksonomy-based web service annotating is
emerging, i.e. to annotate web services with semantic from
community-generated folksonomies. This paper focuses on how
to provide folksonomy-based in-depth annotation of web
services. Herein, the in-depth means the annotation is based on
a structured folksonomy, and steps inside different parts of the
web services in an automatic way. Two problems need
addressed: exploring semantics for the folksonomy from
original tags of web services, and automatically assigning tags
to the different parts of web services. The paper proposes an
approach to achieving automatic tags assignment of web
services with a structured folksonomy. Such in-depth
annotation facilitates web services discovery and composition
by providing precise tagging of input, output and etc. A casestudy
and result of experiments on the pairs of tag-service
extracted from a web service portal, seekda, illustrates the
effectiveness of the approach.