We have a Writer's Forum. Writers here are not only welcome, but are valued members of the community. The writers here tend to partipate a lot in all discussions of interest, and often "advertise" their books by way of links to them or their own website in their signatures. Somewhere around here there's even a singular thread expressly set up to blatantly plug your book.
Of course, if you go around solely go round creating new threads plugging your books, or looking for any thread that might have some remote tangential connection that you think warrants plugging your book (or worse, no real connection at all; if your sole reason to be here is to plug your book with every post, well you'll probably very quickly pick up a pattern that indicates you're merely spamming the forum with ad's. The owners frown deeply on that - expect not only prompt reaction from them, but a negative response from any potential market you thought you might have.
Participate. Don't spam. Get your sig' going. Find the Writer's Forum. Learn the ropes. You'll know when the right time is to mention your books (psst, try the "Introduce Yourself" thread - it's the perfect place to start), or announce new ones. Look for other authors here (eg. Steve Jordan, "starrigger") and see how those valuable, participating members so readily and welcomly fit here (often with announcements waited on by readers with enthusiasm). Whatever you do, do NOT pretend to be someone else recommending your own book (that can be marketting death if discovered).
Jump in. The water's fine. Behave like a member of the community, and the writer that you are will find its place.
But go to the "Introduce Yourself" section. It's the perfect place to tell us who you are, what you're here for ("help" is a valid reason - it's how most of us started here
), and what you write.
Cheers,
Marc