In one of my former lives I was a vet tech (LOL, up until I quit in Aug.) I've asked my (former) boss this question quite a bit, and he's of the opinion that -- with the carpet/lino licking at least -- it's either a stress relieving activity or "just something to do," like people who twirl their hair or bite their nails.
Warning, though, if your dog SUDDENLY and DRAMATICALLY starts licking every surface in your home (taking paint off walls, making obvious "clean spots" on your I-thought-it-was-already-clean lino, etc.) it's can be a sign of Addison's Disease. But that doesn't sound like what your dog is doing.
I live with a dog who spends 45 - 60 minutes a night (usually starting around 9pm) licking the carpet. He's a rescue (off the streets) and supremely neurotic ANYWAY. My former boss and I both think that the repetitive and "scheduled" nature of his licking shows it's a stress reliever for him, and that he probably has some form of OCD (yes, dogs can have OCD!).
Just my $0.02