From The Desk of Liz Ensley:
Coincidence of events that seem to be meaningfully related, conceived in Jungian theory as an explanatory principle on the same order as causality, the relation of cause and effect: The result is the same, however differently the causality is interpreted.
Synchronicity implies a dynamic of relationships or events. Sound familiar? When you write a story, no matter the genre, you want an expressed synchronicity of events and relationships. I think this is often referred to as the "theme" of the story. If you have two people who have not seen each other in ten years, and one is researching, say, Norse vampires, possibly for a story, and the other had designed a gaming system with said vampires, had done research, and by some chance posted something on-line which helped a third party to help the first party focus the search on Norse vampires--that's a synchronicity, if he's on a recent panel discussion about the gaming system and the Norse vampires will be part of the panel discussion. ;-)
Actually, that part just happened in a topic on LiveJournal: but it doesn't have to be the same research or event of real-life synchronicity. In real life, the lead-in isn't quite so perfect, but it gives the writer an idea to play with, for a logical synchronicity within the context of their story. Instead of hearing word about a friend, synchronicity could bring them to the same place, at the same time, and for a related reason.
I'm probably just blowing smoke; but it is still an interesting point to ponder.
Elizabeth Anne Ensley
When I face the desolate impossibility of writing 500 pages, a sick sense of failure falls on me, and I know I can never do it. Then gradually, I write one page and then another. One day's works is all I can permit myself to contemplate.
- John Steinbeck