Behold, the dragonchild stirs and breathes fire, burning away the misty clouds of ignorance from mine eyes.
I am humbled at the agility of the human parser which so easily recognizes words such as "asohsle".
Verily, the darkness is great before me, yet there is light in offing and I see the way to win small battles.
There are three regions which I must protect:
1 - Usernames
2 - Message Board postings
3 - User writeups
The first is perhaps the easiest. It will be limited to [\w-_]{6,20}. This reduces the possibilities. Perhaps a three-level process; first substitute out all hyphens and underscores, then m/a+[s5ho0l1]{4,}[e3]+/i, if true try to match a more detailed list of regexes. Also, in this case, I can be as tough as I like without having to explain why---I can simply say, "The password you chose is in use" for anything iffy.
The next two are more complex, however, they are not time sensitive. Once a user makes a posts a message to the board or a writeup, I can mark it viewable only by the user and admins until it can be parsed by a more determined script. If that script determines there is anything troublesome, it can notify an admin to view and approve/disapprove/edit it before making it available or deleting it. Further, I can allow users to flag such items if they are offensive, again to be reviewed by an admin. This process should handle the 'two chicken breasts' for everyone except any fowl who may be on the site (I discriminate against no lifeform). As for the 'pus-dripping son of a motherless flea-bitten camel', I am sure the admins will make the appropriate reprimands once it is brought to their attention. The important thing is to prevent young eyes and their parents from inadvertantly seeing anything that can be avoided with reasonable caution.
Again, I give thanks for your gift of enlightenment. I shall be stronger knowing better the foe I face.
Yea, though I tilt at windmills, I am sworn to the quest. Come Sancho, the contest begins...
"Peace, love, and Perl...well, okay, mostly just Perl!" --me
Apprentice