By chance, I discovered that one of my pieces in Fiction had been indexed by Google. Then I checked phrases from other threads, and those threads turned up in Google search results too. Confused as to why Google was ignoring requests not to index pages, I looked at the html source code of the Fiction pages, and found that the code that asks search engines not to index pages was missing.
I've flagged this up to Alex. He is very busy at the moment, and says it may be a while before he has the time to investigate and fix the problem.
In the meantime, he advises using the [noindex][/noindex] bbcode tags.
So, you're concerned about search engines, when you start a thread in Fiction, add [noindex][/noindex] to the top of your post.
Note that the [noindex][/noindex] tags should have nothing in between them. They just open and then close. Because they're bbcode, they won't be visible when you post your post.
These tags will only protect the page they have been added to, so if the thread stretches to more than page (pretty rare in Fiction!), the first post on the next page will also need to also contain those tags at the beginning of the post. You can ask the person who posts the first response on that page to edit their post to add the noindex code to the top of it, or if you can't get the poster to do it, you can ask a moderator to do it.
See also this thread, in which Alex explains the various ways in which the Sphere is protected, and explains the noindex bbcode
I want to stress that this is only the case with the Fiction forum. The poetry workshop forums are as well-protected as they've always been.
Matt