heres a list of social bookmarking sites i have used in the past
i wont list them all at once as theres hundreds
heres 50 to start with
some may be dead now
netscape.aol.com/
w3.org/2001/Annotea/
slashdot.org/
myweb.yahoo.com/
video.google.com/
googlesystem.blogspot.com/2007/09/google-shared-stuff.html
youtube.com/
flickr.com/
photobucket.com/
digg.com
mystuff.ask.com/
technorati.com/
del.icio.us
stumbleupon.com/
simile.mit.edu/
furl.net
9rules.com/
odeo.com/
propeller.com
rojo.com/
bookmarks.yahoo.com/
myweb2.search.yahoo.com
google.com/notebook
myaskjeeves.uk.ask.com/
slide.com/
esnips.com/
twitter.com/home
wikia.com/wiki/Wikia
reddit.com
box.net/
ifilm.com/
blogcatalog.com/
topix.net/blogs
meneame.net/
taggle.de/
fark.com
shutterfly.com/
43things.com/
metafilter.com/
tags.library.upenn.edu/
newsvine.com/
matrix.msu.edu/
techmeme.com/
ma.gnolia.com
linuxquestions.org/bookmarks/
rollyo.com/
swik.net/
icerocket.com/
simpy.com
eventful.com/