Personally, I believe that at this point in time, the option for anonymous posting should be removed myself. I don't think that it is asking too much for someone to provide an email, username, and password for posting. Moreover, it would not only make spamming quite a bit harder, and ensure that innocent parties who are in a public computer/i.p. address situation don't get banned along with anonymous spammers, it would also eliminate the issue where people forget to log in and are then unable to save their work, because doekaki will not allow the applet to be opened without being logged in when anon posting is not allowed.
Overall, it is my belief that the disadvantages to the allowing if anon-posting outweigh any advantages, though that is just my opinion and everyone can take it for what it is worth.
i agree with draikonis. maily about the forgetting to log in and save work issue
. i have never noticed a spammer, either neon does a great job or i am lucky enough to not see it