Quite often, before choosing a restaurant, or buying somewthing, or hiring someone to work on my roof, I check the web for reviews. Occasionally I find a suspicious pattern—lots of very positive and rather generic reviews, along with a smaller number of very negative reviews that sound as though they were written by real people—which suggests that the positive reviews are fakes, written by someone working for their subject. On one notable occasion, that pattern warned me off of a roofing firm that, I concluded, was the third generation of a serial scam. There exists at least one online firm whose business is improving a firm's online reputation—I do not know enough about them to say whether they restrict themselves to honest ways of doing it.
Recently, looking for a furniture store, I came across what I thought might be a less clear version of the same pattern. The reviews were on Yelp, which lets you click on the name of the reviewer and see the rest of his reviews. If all of one reviewer's reviews are in praise of a single firm, one might suspect that he works for them—and his job is writing favorable reviews. The reviewers I was looking at did not fit that pattern.
Which started me wondering how sophisticated the people who sell the service of improving a firm's reputation might be by this time. Are there some who deliberately create believable reviewers, write real reviews of a number of products or businesses, and then sell the service of having the same reviewers write glowing reviews for anyone who will pay for them?