Copied verbatim from A Knife And A Quill blog. I know they won't mind.
I agree with the sentiment 100%

I’m delighted to be able to put my name to the statement below. (Sorry folks but I accidentally published slightly prematurely on that and don’t want to take away anything from my fab co-authors who worked through the weekend and the night to get this together).
Please feel free to copy this letter and distribute as you see fit. I feel a bit sick and embarrassed my clumsy fingers publishedy it first (too much time on the bloody laptop over the last 72 hours). For everyone who’s said ‘Can I add my name too…’ we had hoped to have a system that would enable this. But it’s technically a bit beyond us at the moment. And to be frank we’re all pretty knackered after spending most of the weekend on this and little else. If there were an easy way… We haven’t found it yet but people are still looking.

These days more and more books are bought, sold, and recommended on-line, and the health of this exciting new ecosystem depends entirely on free and honest conversation among readers. But some writers are misusing these new channels in ways that are fraudulent and damaging to publishing at large. British author Stephen Leather recently admitted that he used fake identities online to promote his work. The American bestseller John Locke has revealed he has paid for reviews of his books. The British author RJ Ellory has now confessed to posting flattering reviews of his own work and to using assumed names to attack other authors perceived to be his rivals.

These are just three cases of abuse we know about. Few in publishing believe they are unique. It is likely that other authors are pursuing these underhand tactics as well.
We the undersigned unreservedly condemn this behaviour, and commit never to use such tactics.
But the only lasting solution is for readers to take possession of the process. The internet belongs to us all. Your honest and heartfelt reviews, good or bad, enthusiastic or disapproving,­ can drown out the phoney voices, and the underhanded tactics will be marginalized to the point of irrelevance. No single author, ­ however devious, ­ can compete with the whole community. Will you use your voice to help us clean up this mess?
Linwood Barclay, Tom Bale, Mark Billingham, Declan Burke, Ramsey Campbell, Tania Carver, Lee Child, Michael Connelly, N.J. Cooper, David Corbett, Ruth Dudley Edwards, Stella Duffy, Jeremy Duns, Mark Edwards, Chris Ewan, Helen FitzGerald, Meg Gardiner, Adèle Geras, Joanne Harris, Mo Hayder, David Hewson, Charlie Higson, Peter James, Graham Joyce, Laura Lippman, Stuart MacBride, Val McDermid, Roger McGough, Denise Mina, Steve Mosby, Stuart Neville, Jo Nesbo, Ayo Onatade, SJ Parris, Tony Parsons, Sarah Pinborough, Ian Rankin, Shoo Rayner, John Rickards, Stav Sherez, Karin Slaughter, Andrew Taylor, Luca Veste, Louise Voss, Martyn Waites, Neil White,  Laura Wilson, Darren Sant