to leave it up to admins (with a pretty restrictive default-set of legal tags). to the "evil" tags i'd add "layer" and "ilayer", and maybe "span" and "div". and one could also try a legal tag together with the "style"-attribute to destroy a layout, or some event-handers ...

let's face it, if someone messes with macros or with "class" and "style" attributes just to annoy you, you simply delete the message. on the other hand everyone can write complete bullshit. this is actually a bigger problem, because it does not require any intelligence.

i think it is important to block everything that could be a possible security hole. i wouldn't worry about the attributes.

another problem arises with tables. some browsers don't display pages if the "table" tag is not closed. looks like you either need a validiator script or you close open tags at the end of the message. (and maybe you should allow the admin to edit everything to correct these things.)

it's a little bit off-topic, but generally i agree with kris that the bigger problem is (ie. can be) the content between the tags, just think about why yoobay has left the building.

i've experienced too much trouble with funny people trying to learn html in discussion-boards ... it really can be annoying if somebody craps your page by using simple style-attributes (i forgot one tag: "embed" is also pretty dangerous ...)

but i agree that the content between the tags can probably be a bigger problem ...

that admins should be able to edit everything. I sometimes have to do this for not-quite-right links tags on henso.com comments. (I'm using the helma inspector for it.) I think a site admin should be trusted to do this. It's a technical and ideological issue more than an editorial one: A site is owned by its admins like it was on their own harddisk. Whether the folks owning an Antville site implement a sensitive editorial policy is up to them, we can't (and shouldn't try to) force it upon them.

Now having an "edit" link next to each comment would certainly give the wrong idea. Actually, I also find that having a "delete" link next to each comment has some kind of strange taste to it. What I would propose is that admins get one "admin" link for comments from other people, and from there on can edit or delete them.