I know and I have worked on tagging in blog posts..etc I just saw a paper which says how to automate tagging in web services. But what do you exactly mean by tagging in case of web services?
Solution
A tag is a non-hierarchical keyword or term assigned to a piece
of information.
This kind of metadata gives a brief description of web services
and makes users find proper services more easily, categorize
web services and make web services management more
effective.
Tags allow cross-browsing between documents.
Tags can be used as keywords for search engines and this is
helpful to improve the performance of search engines.
Tags can also be used as a feature in query expansion systems
and recommendation systems.