Unfortunately, I have no way of correlating book sales with my participation in any of the smaller sites listed below. By no means am I selling a ton of books, although Mirrors & Mist is off to a much better start than its predecessor, Crimson & Cream. Whether any of these websites contributed to that, I've yet to discover.
I'm fully aware that my posting on these websites may have accounted for exactly zero sales, and that I may have done nothing more than expose myself to more scams, spams, or worse. However, following the old adage of There's no such thing as bad publicity, I did what I did.
So far, I haven't noticed any negative impacts (knock on wood), although shortly after joining Bookbuzzr, I noticed a curious influx of Google Plus additions by what appear to be fake accounts (no posts, real name, or actual photo). This may just be a coincidence, and there's no real harm, since I don't add people that don't appear to have legitimate accounts. Anyhow, this isn't an endorsement for any of these sites, just a listing for those of you curious to explore them for yourself.
If you have experience (good or bad) with these or any other similar sites, I'd be interested in hearing about them, if you'd post below.
Also, in promotion for the Mirrors & Mist release, I'm giving away free copies of Crimson & Cream at Smashwords for a limited time with this coupon code: HB78A. Feel free to share.