File formats and codecs
The CouchSurfing Wiki, an informal workspace which anyone can edit.
Currently a lot of files on CouchSurfing are in formats and codecs that ideally should be avoided, because of patents, and possible law suits in the future.
Wikipedia (and more specifically the Wikimedia Commons) has a list of formats that are accepted at Commons:File types. The Wikimedia Foundation is very careful with law suits and it is also getting a lot more media attention. Their experience and expertise is openly available and should ideally be taken into account.
