Electronic discovery (or e-discovery or ediscovery) refers to discovery in litigation or government investigations which deals with the exchange of information in electronic format (often referred to as electronically stored information or ESI). These data are subject to local rules and agreed-upon processes, and are often reviewed for privilege and relevance before being turned over to opposing counsel. Data are identified as potentially relevant by attorneys and placed on legal hold. Evidence is then extracted and analyzed using digital forensic procedures, and is reviewed using a document review platform. Documents can be reviewed either as native files or after a conversion to PDF or TIFF form. A document review platform is useful for its ability to aggregate and search large quantities of ESI. Electronic information is considered different from paper information because of its intangible form, volume, transience and persistence. Electronic information is usually accompanied by metadata that is not found in paper documents and that can play an important part as evidence (for example the date and time a document was written could be useful in a copyright case). The preservation of metadata from electronic documents creates special challenges to prevent spoliation. In the United States, electronic discovery was the subject of amendments to the Federal Rules of Civil Procedure (FRCP), effective December 1, 2006, as amended to December 1, 2010. In addition, state law now frequently also addresses issues relating to electronic discovery. Other jurisdictions around the world also have rules relating to electronic discovery, including Part 31 of the Civil Procedure Rules in England and Wales. Individuals working in the field of electronic discovery commonly refer to the field as Litigation Support.