No matter what world you're in, your characters have to communicate. How do they do it?
Games have everything from Star-Trek style communicators to radios to standard cell phones. One of my favorite fantasy series, the Chronicles of Elantra, has magic mirrors--in fact, mirror scrying in different forms is a pretty common fantasy substitute for cell phones, or at least phones. Scrying's pretty common, too. Role playing games live on the principle of never separating the party, but even if you do, there are message spells to communicate back and forth. Or you could always send an owl.
Low-tech worlds, meanwhile, rely on older forms of communication, such as sending runners. That can make an interesting plot point, because the messages don't always get there in time. But instant communication is something many readers in this day and age have come to expect, and it shows in modern stories.
What are your favorite methods of fantasy communication? Of the books you've read that are recently published, are there any that don't have instant communication? And there any fantasy worlds that make especially good use of the lack of communication?
(Hello, it's Monday! Er, wait, what happened to Friday? Oops... Here's some photos for public domain as apology...)