Unlike data mining, text mining has received only limited attention in legal circles. Nevertheless, interesting legal stumbling blocks exist, both with respect to the data collection and data sharing phases, due to the strict rules of copyright and database law. Conflicts are particularly likely when content is extracted from commercial databases, and when texts that have a minimal level of creativity are stored in a permanent way. In all circumstances, even with non-commercial research, license agreements and website terms of use can impose further restrictions. Accordingly, only for some delineated areas (very old texts for which copyright expired, legal statutes, texts in the public domain) strong legal certainty can be obtained without case-by-case assessments. As a result, while prior permission is certainly not required in all cases, many researchers tend to err on the side of caution, and seek permission from publishers, institutions and individual authors before including texts in their corpora, although this process can be difficult and very time-consuming. In the United States, the legal assessment is very different, due to the open-ended nature and flexibility offered by the “fair use” doctrine.