Startup microstock sites have to be pretty good these days to make an impact, clusterstock seems to fit this bill, except for the fact that they not a true microstock agency. Slick site operation (it's simple things like automatic calculation of your commission when you enter the price of your images that please), import photos from an rss feed or a zip file along with importing images from a flickr account.
The terms and conditions make interesting reading, but I do hope that someone with legal knowledge has looked over them "Be good and don't do anything malicious" sounds nice as does the first term about you keeping all the rights to your images.
Price of 10 dollars reflects an average of what I have seen, prices can be chosen by you the photograher.
One thing to highlight is that clustershot make a point of themselves as "facilitating the sales of images", i.e. you send the buyers to them using the links provided with each image. Of course buyers will also be able to buy images if they find them by searching from the sites front page.
clustershot do not review images that are placed on sale, so all liability will fall on the photographer. Like mostphotos.com take care when uploading images as there is nothing to stop you from uploading material (photos of people etc) which may later land you in trouble if you do not have the required model or property releases.
This site was a joy to review, I was able to import several hundred flickr images (although I only upload web resolution images to flickr) and also upload several months worth of my microstock portfolio in just a couple of hours. If you had read the previous version of this post I noted the site had one major limitation, it did not import your IPTC keywords. Like all good sites Clustershot have been listening (you'll see a comment below) and they now support import of your IPTC metadata, this makes uploading simple. The upload system is good, you can either browse for a jpeg image (one at a time) of if you select a zip file with several images inside it the site will expand it meaning you can upload up to 100MB of images in a single shot.
To put it simply, it works, and the user experience is "everything where you expect it to be".
Preliminary Conclusion
While RSS and Atom feeds might be the future of photographers 'streaming' their work to those who want to sell it, I'd still like to see FTP upload to fit into the rest of my workflow (uploading a ZIP file is a convenient alternative for now).
If suitable plugins are developed for gallery software or websites (noted that the developers of clusterstock already have a plug in for their own opensource 'pinhole gallery') then with clustershot taking only 12% commission from the sale this could be a very cost effective way of letting a 3rd party deal with sales of microstock. Certainly for full priced stock images then manually linking up galleries to clusterstock images could be quite cost effective.
As usual I can't give any more information about expected sales levels as this is such a new site and because clustershot is not true microstock I can't draw direct comparisons, since the support for IPTC came along I've been uploading but not quite in the same way as I do the other microstock agencies. I will be monitoring the results with the acknowledgement/caveat that I am referring buyers from a travel photo site that will (hopefully!) reflect in my earnings.
Jan 2010, So far just a few sales.

ClusterShot New Features
Dan James (not verified) on Tue, 02/10/2009 - 16:36Good to hear it
Steve Gibson on Wed, 02/11/2009 - 17:20I look forward to it, and I understand that with slightly less than standard 'standards' around IPTC/XMP implementation it's not such a straight forward process as it first appears, do keep me informed (or indeed all users of your site) with any new features and i'll update the review.
thanks, steve
IPTC Tagging
Dan James (not verified) on Tue, 04/07/2009 - 15:00Thanks
Steve Gibson on Thu, 04/09/2009 - 01:02Thanks for the update on the number of images. From what I understand 100,000 is the magic number that a new agency needs to get started (provided i guess it's a well rounded collection).
"It's fairly lightweight to run right now and we are dedicated to its long-term success"
I like what i hear in that sentence, with the cost of storage and bandwidth falling exponentially, I can't see why any well thought out e-business should ever have to close or use some excuse about the "economic crisis". That might be over simplifying things, and when I said the same statement at a recent conference was was met with general disagreement. But I think its true, especially if the business model can continue to run day to day on incomes from sales, and letting end users do their own marketing - a subject which a lot of "2.0" photographers are getting quite smart about.
WebDAV uploading
Dan James (not verified) on Mon, 08/03/2009 - 14:01Update
Steve Gibson on Tue, 08/04/2009 - 02:41Congrats & Pro Accounts
Dan James (not verified) on Tue, 08/04/2009 - 18:58