Human nature remains the same, despite technological and social change. The Brave New World of the 'Net, for instance, is moving with breathtaking speed from idyllic frontier --- leave your front door wide open, trust all your neighbors, work hard and play hard together --- to gated urban community. Besides the carcinomas of spam and virus/worm/denial-of-service attacks, consider the proliferation of:
Sure, equivalents to all of the above exist commonplace in the non-electronic universe. They're also quite annoying and in some cases, when egregious enough, have led to legislation and real-world punishments.
On the local ZhurnalWiki front, sporadic potty-mouth graffiti attempts aren't (yet!) a significant problem. Auto-posted advertisements and the equivalent in manually-posted commercial promotion, however, threaten to become troublesome and may some day require further gentle modification of the wiki model --- or so I anticipate. (For instance, at present images have to be located on the zhurnal.net domain before they're auto-loaded; it's an option that wikimeister Bo Leuf implemented last year after some unæsthetic antisocial behavior was observed on another wiki site.)
Maybe a trivial challenge-response system, to deter robot posts ... maybe a moderator, human or AI ... maybe a shared password or other handshake-authentication mechanism? Or maybe none of that is necessary, at least not for a while. I sure hope so! (And if you want to help, please tell me if you see something out of line here, or simply edit the appropriate ZhurnalWiki page to fix it yourself. Thank you in advance!)
The best analogy to this problem: gardening. Sometimes you need to install a little fence to keep the bunny rabbits out of the carrot patch ... sometimes you need to pull up a few weeds ... sometimes you need to trap and exile a mole. And sometimes, to get even more technological, you need a slightly tricky bird feeder to keep the squirrels from stealing all the food ...