By ChrisPhoenix. Inspired mainly by WikiWiki, CritLink, and XeroxSparrow.  Anyone who signs in can add comments in the middle of other people's pages (like Wiki) but the comments are owned by the author (like Crit).  Still under development; the source code will be Open Source; write me if you want an early copy.  

Oh yeah, it's at http://www.xenophilia.org/xenostart.cgi .