Bait and switch of content is considered spam in Dmoz

A very good explanation by an active Dmoz editor named hutcheson on switching content on domains, Dmoz on strict on content quality of sites and when someone cheates by switching content site will be removed from dmoz, A very good explanation below,

"Bait and switch" is when we list a site based on its content, and then the
webmaster changes the content to something else "not related." For us, it is
sabotage -- the single most harmful thing a webmaster can do to the directory.
We take it very seriously. Normally we immediately go on a crusade to expunge
all that webmaster's sites with extreme prejudice. This is not "revenge" -- this
is our way to protect the directory from further acts of sabotage.If we weren't
talking to you here, that's where your sites would be already. They aren't yet,
but you need to understand that this is deadly serious to us. And, now that you
understand that, there need to be no more "switches." OK, for now both sites are
removed from the directory. I repeat, this is not the permanent ban. Yet. Since
you're here and we can talk to you, we can try to start fresh. Another background
bit of information: the ODP is not a listing service for the benefit of you, the
webmaster. It's a site finding service for the benefit of surfers. Our guideline
is: if a site is useful for surfers and we can list it, then we do. There are two
parts there. It has to be useful. And sometime in the past, your automotive site
convinced an editor it might be useful. (That's a high compliment -- most
automotive classified sites are not accepted.)But the other part is, we have to
be able to list it. And this implies, we have to have a definition of a "site"
so we can distinguish what constitutes a "site"; that definition has to
distinguish few enough different "sites" that we can list them all. This means
we don't try to list every page of every site: just the main page. And when we
see one entity with multiple domain names, we treat all the content on all the
domains as one site, if that makes sense. Now, classified ads sites are, um,
oversubmitted. Most of them are worthless, and many people who have a
classified-ads engine try to abuse us by creating lots of little sites that use
the same (or similar) engines on lots of different topics, and then submit them
all to us. But much larger, name-brand, reputable classified-ads sites have only
one listing because they aren't depending on spamming us for their promotion, so
they put everything on one domain. That's not fair to the users, and it's
certainly not fair to the good sites. So we are very strict on "entities." One
entity, one site unless there's a really good reason otherwise. And having
several different classifications of ads is not a good reason. Here's where you
came in, unwittingly imitating the techniques of the "ancient legions of
big-time spammers." And -- no problem, we know how to handle that, we've had
lots of practice: "Find the main page, list it, problem taken care of." We don't
want much flexibility in the guidelines here: we're better served by letting you
link to all your own pages (no matter what domain they are on) and leting us
focus on reviewing someone else's site. Until the bait-and-switching started up.
(Well, we know how to solve that problem, too, if necessary.)So we won't ask
"how can you get two listings?" We'll discuss "do you get one or zero listings?
If you get one, which is the best URL to use, and which is the best category to
put it in?"So talk to us:-- Commit to one main URL (we don't care how many other
URLs you have so long as you don't submit them; if you need to change the main
URL, we have an "update URL" link)-- Commit to leaving the major types of
content be accessible from that URL (we don't mind additions or changes in
content, so long as the description we have still remains accurate -- or you
request an "Update URL" to correct it).-- Get the basic links in place (we don't
mind site redesigns) and we can look at the site. The forum limits apply: we
can't argue about placement, but we can make sure we're seeing the content you
meant to feature.