Here's where shit gets real, where the spiritual connects with the realm of matter. So to the materialist (ie, me, most of the time), this is the only realm that actually exists. I am in Malkuth, looking up. Or out. Or something.
Due primarily to the neo-platonic influences in the Kabbalah, Malkuth also is typically seen as a locus of evil, since the real materialized world can never measure up to the ideal. Anything coarse enough to actually exist has to be imperfect, hence distinct from the good, hence evil. This has to be one of the major bad ideas of all time, responsible for so much denial of reality and denial of the flesh and concomitant misery. Nonetheless, my assumption is that such a powerful idea must have an element of truth to it, or it would not be so persistent and pervasive, and reflected in so many things. For example, look at occupational status -- the more your job involves dealing with the physical on a day-to-day basis, the lower status it is, broadly speaking. It's interesting that there are exceptions to this general rule, such as surgeons and sculptors, and cooks at a high enough level. And you can look at the Maker cultural movement as an attempt to further elevate the status of the material. But in general people who push matter around for a living are beneath those who push words and symbols around. At this very moment I have people doing construction on my house, and while I have nothing but respect for their craft, the status differences are there and hard to ignore, although we try to do that here in the US.
Matter is also identified with the female (look at the etymology). It is receptive. In the Omer it represents an endpoint, the point where the Jews received the law at Sinai. That's another picture of the materialization of spirit. The Torah has an almost idolatrous place in Jewish life as a result, it is paraded around at services so that the community can touch it (of course idolatry is forbidden in the Torah itself). It's very strange, when you think about it, but apparent self-contradiction is just part of the religion game, all oppositions get reconciled in the infinite. Or something. God materializes into the law which materializes into scrolls which we can see and touch and read. Judaism itself has materialized itself around this particular document and practices, and old and strange thing, a community and set of practices which draw me in despite myself. I can't defend it, and I don't really have to. Judaism doesn't proselytize, it's not a belief system, it's the original community of practice. I find myself at the margins of it (and many others), drawn in a bit, repulsed a bit, trying to find a balance.
Malkuth is also identified with speech and expression, it is the locus where the inexpressible divine energy crystallizes as mere words. OK, not "mere" words, but words that somehow reflect authentic presence, that carry the holy fire. In today's world, where the written word is insanely abundant, where everyone's words are instantly uploaded, indexed, chopped up, and linked to ads by the trillions, it is hard to imagine what the earlier relationship with words was like -- before the internet, before printing, before mass literacy. It is strange that ancient attitudes and practices have survived the turmoil and inventiveness of the millenia, but there it is. "The past isn't dead. It isn't even past."