I got a drive by review--a clearly personal attack--from someone who had been at a convention where I was a guest. Something I said at the convention made its way into her commentary.
Which I found rather amusing. I knew who it was, her motivation, and marveled that she thought I'd not notice.
I reported it to Amazon, pointing out that there was no review, just comments about me as a person. Thankfully, they agreed and removed it.
If you think you've gotten a slam like that, then absolutely report it.
Let Amazon do the dirty work.
But never--and I mean NEVER!!!!--engage the reviewer online in any way whatsoever.
I'm sure a few here will recall a batshit insane paranormal writer who went looney-toon over a 3-star review and got into a public donnybrook with the reviewer in the Amazon comments. Sides were formed up, tears were shed, and it's a miracle the writer's agent and publisher ever spoke to her again.
Non-professional behavior can kill your career.
Not everyone is going to love your words. That's part of the job and you shrug it off. But if it looks like the reviewer has an agenda beyond the limits of offering an opinion on one's book, call in the marines.
One of my pals even agreed with a few of the 1-star reviews. "They had valid points."
Or, you can quote the bad reviews on your website, but make sure you're funny,
like Preston & Child:
Reviewer:
"I decided that I would have to finish this book, even though I knew at about the half-way point, I would have to dispose of it so that at least there would be one fewer copy on the face of the earth...The science is so weak as to be embarassing. More than embarassing, absolute garbage, even taking into account poetic license. To anyone who believes that this is a quality novel, or anything beyond toilet paper, all I can say is 'There are good scientific thrillers out there, these authors couldn't write one, even if they were copying one word-for-word.' "
The authors reply:
"Ouch! Don't get all hot and anxious about my poetic license, that was revoked last year. And by the way, there are two 'r's in 'embarrass.' "
-- Lincoln Child
"Not good science? Why, before writing RELIC, we did extensive scientific research on the worldwide problem of brain-eating monsters infesting museums. What more could you want?"
-- Douglas Preston