As far as I see the ones that are marked closed are not visible for me. Maybe only at admin-level? I am not sure, but are the closed ones still visible under the articles itself?
I think I have closed a couple, where there were the first response to an article. As mentioned above it would be nice to be able to clean them up as well, or have a report function as we have in the forum. (which would be possible both if the discussions would become part of the forum, as you suggested before.)
Okay, I've closed that discussion now then. One thing you can do to alert me to these in the meantime until a better solution is in place is report the member using the link on the profile pages. I try and check these reports daily, so do get to catch most things that come through that way!
okay, will do.
spamloving people be warned 
Standard you can just close them, and not delete. That basically is the problem in my opinion. I think the admins and moderators (at least the travelguide ones lol) should be able to delete them. It is not much work and most of the spam is not in that place either. The ones that are, are so obvious they should be deleted, not closed. Don't get the intention of a closed thread if you can not find it anywhere as well.
Or is closing the same as deleting? Would not be could idea, because a discussion can be great, but one spam and the whole thing should be closed.
Another delete function for a specific reply (just like the forum) would be easy and the only logical option.
Quoting Utrecht
Standard you can just close them, and not delete. That basically is the problem in my opinion. I think the admins and moderators (at least the travelguide ones lol) should be able to delete them. It is not much work and most of the spam is not in that place either. The ones that are, are so obvious they should be deleted, not closed. Don't get the intention of a closed thread if you can not find it anywhere as well.
Or is closing the same as deleting? Would not be could idea, because a discussion can be great, but one spam and the whole thing should be closed.
Another delete function for a specific reply (just like the forum) would be easy and the only logical option.
Strange, no reply here.
The thing is still up to date though: there is regular spam, but also just question which belong in the forums, at these travelguide discussions. Also, you can only mark a thread as closed, even if it is just spam.
Also, sometimes there are a sort of deadlines by members, and as it is read just by a few people, it is better to have the travelguide forum for discussions. There is no added value to have this here.
Actually, since this post the spam area behind the scenes has been greatly improved, so member reports are dealt with much much faster now. But yes, this specific case of the wiki discussions is still outstanding. Moving all the discussions to the forum is really the only thing that makes sense to me, but it's also a much more involved change than just adding a delete option.
I'll have to check with Peter if he's okay with moving this all over to the forum, and if so, I can probably start work on this next week... no promises on how long it might take me to get the coding finished though! 
No hurries Sam
Didn't know things were actually better and faster, as I noticed a few olders spams today. Have to admit: I check it very irregular myself, but I'll try to keep on eye on it more for the next weeks or so.
Cheers