An article that might be of interest to you, "Using Hadoop to analyze the full Wikipedia dump files using WikiHadoop".
If you are after Wikipedia page view statistics, then this might help. You can download pagecount files from 2007 up until current date. Just to give an idea of the size of the files, 1.9 GB for a single day (here I chose 2012-05-01) spread across 24 files.
Currently, 31 countries have sites which make available public data in various formats, http://www.data.gov/opendatasites. In addition, the World Bank makes available data at http://data.worldbank.org/data-catalog
