There are other accounts already on the case. The American Bar Association has a summary (with some of the reported fact pattern) here. The "Inquisitr" has a valuable article on the underlying debate and how it could affect the "consumer review site" industry here.
Update: March 27, 2015
The NBC Today show covered this incident briefly, and conducts a survey that reports that 87% of respondents report that review sites affect their purchasing decisions. I replied "No", although I sometimes look at hotel reviews (does the WiFi work?) and movie and theater reviews. Frivolously, an actor said he wondered if Hollywood would sue critics.
The UK Daily Mail has a story by Evan Bleier, and the comments are interesting. The story also has screenshot illustrations of the review process. One comment suggested the defendant use "GoFundMe". That strikes me as a bit tacky, but the defendant probably does get a lot of "free publicity", which maybe she didn't want. The business owner is likely to get resentment from the public for merely filing the suit, which may hurt business more than the review itself.
Update: March 29
Rick Callahan, on p. A3 of the Sunday Washington Post, in discussing protests against Indiana's new "religious freedom" law. notes that Angie's List has considered adding (or moving) 1000 jobs in Indiana (link here). Wikipedia says it has over 1600 employees now. I had no idea that a review site company could need so many employees and was this big! In fact the Indianapolis Star reports more detail about possible cancellation by Angie's here. The company had planned to rehab a run-down area of the city (in which I worked for the summer in 1970).
Update: April 1
There has been a sequence where people posted negative reviews of an Indiana pizza place over its position on gay marriage, with the reviewers never visiting the place, on Yelp, story by Robby Stoave on the Hit-Run Blog on Reason.