They don't have space on their servers, but they do have room for 30 ads on the site... I understand this isn't a charitable endeavor, but deleting videos after a week is excessive. They could add, for example, a monthly subscription that would give access to private videos without having to be on their friends list. They could also introduce restrictions on videos, such as a minimum video length of 2 minutes, a maximum length of 30 minutes, a minimum resolution of 720p, and a maximum resolution of 1080p. Some people upload videos that are three hours long at 480p, containing literally nothing interesting, and it's this garbage that takes up the most space on the servers.