rel attributes which could, potentially, be used in microformats.
This appears to be a potential (perhap unintentional) attempt to bypass the The microformats process. Abstract examples of rel attribute values if anything are more akin to existing formats rather than examples.
Rather than listing any such rel attribute uses here, if there is a desire to actually rigorously develop the functionality behind such rel attributes into a microformat, then the The microformats process should be followed with that functionality in mind, rather than a paticular rel attribute value. Tantek 15:00, 21 Jan 2007 (PST)