Cats communicating with scent is possible because they have a fine sense of smell, much better than ours. It so good that they have developed a vocabulary around it. This vocabulary is as good as the written word filed away in the filing cabinet or posted on a banner over the shop front. It is also as precise as the written word and much more precise than some of the stuff written by some humans :)
Fair enough, we also use scent to certain extent to send signals usually to the opposite sex, with perfume for example. Strange though that we have to cover up our own smell with something artificial? It must mean we don't like our own smell. Cats don't have that low self-esteem so they're better than us in that area too.
How do cats make transmittable odors? Feces, urine and scent glands. I know it sounds a bit gruesome for humans but we are really too sensitive about these things.
I've talked about Timmy a boy cat who has entered our lives here in London (he's just walked in by the way - hi Timbo how yu doin mate - meow (I want food) - rub rub (scent transmission to me). Timmy rubs me with his scent glands endlessly as a friendly greeting and I return it. He's communicating loud and clear.
He may (I don't know what he does outside) also leave his feces either covered or uncovered after going to the toilet. He's a stray cat and if he's boss cat in a group he may feel minded to leave it uncovered to send out the signal that he doesn't have to hide and be subservient but is top man.
Cats are territorial. Spraying urine on a prominent area sends an obviously clear signal - "this is my area stay out" (like a red light). This avoids confrontation. If the urine is old the "red light" of fresh urine is turned into the "green light" of old and the way becomes clear for others to come through.
Both scent transference and spraying also provides a comfort zone for the cat as he is surrounded by friendly scent.
Where's the filing cabinet I got some **** to put in it.....
Photo - creative commons copyright Sheila Steele (Flickr)