Tagging in a wiki is quite easy: If i want to collect "jobs for newbies" i just create a page "jobs for newbies" and list all the jobs for newbies. Everything is much easyer if we also have backlinks. then i add the a link to "jobs for newbies" to the task i want to tag, and on the bottom of "jobs for newbies" i find this task under "items tagged with 'jobs for newbies'".
(Would we need labels/etiketten anymore then?)