It could have been del.icio.us with its army of users tagging keywords on every URL. The way del.icio.us does curation is smart in many level. Spammers need to

It could have been del.icio.us with its army of users tagging keywords on every URL. The way del.icio.us does curation is smart in many level. Spammers need to create many accounts to affect tags they care about.