You don't need to have your own website to be an SFI affiliate, however having your own website will make your campaign limitless, you can add everything you want in your website or you can select what you want to promote from SFI or Triple Clicks. Sometimes some links of SFI are banned from social networking sites like facebook, so instead of using SFI's gateways you can use your website as a gateway to your links. ^_^.
