First, UGC should be publicly accessible (publication requirement). The DECO thereby explicitly refers to the internet as publication medium understanding UGC as one of the main features of the participative web and mode of expression in the new media era. Platforms of UGC distribution included internet forums, feedback and review sites as forms of the first UGC wave as well as blogs, wikis, social networking sites, online video sites, social content aggregator, bookmarking sites, podcast sites, and virtual worlds as venues of the second UGC wave24 (for definitions see Appendix I). According to the DECO the publication requirement excludes non-publicly accessible forms of two-way communication such as email and instant messages. The linkage between UGC and the internet seems to be widely shared.