If you are going to fail because your assumptions were wrong, do it before you waste your time and resources.
This applies also to promise of Linked Open Data as a data source for analytics. Just that certain data is published does not mean it is useful for certain type of tasks.
This case study here shows how do you quickly validate a semantic data source from quantitative and completeness perspective.
First slideshare on Explore&Quey : http://www.slideshare.net/JrgenKerstna/can-spsrqlexplore-query-with-vinge-tutorial