The NCSA httpd 0.4 release in 1993 announced support for Group Annotations, which was basically this. So all of you "I had this idea four years ago" people need to get in line behind Marc Andreesen, who had this idea, dear god, 16 years ago.
It never really took off--I think even though httpd supported annotations, I don't think Mosaic itself ever really did.
The power to destroy a planet is insignificant when compared to the power of the Force. - Darth Vader