Stacy Lawrence, my wife, owns Make An Impression  in River Edge, NJ. Very early on I saw the impact that reviews can have on building credibility. I encouraged her to encourage clients to review her store on Yahoo (this was before Google, The Knot, and Wedding Wire became such popular review platforms).

There was no local wedding invitation business retailer in the Northeast that had more reviews on Yahoo than her store. Then, several months ago, we checked her profile–her entire review history had been wiped out, replaced with a single Yelp review.

We researched this and found that Yelp and Yahoo formed a partnership where, going forward, reviews on any business Yahoo profile would posted on the Yelp network  The caveat was that until a business was reviewed on Yelp, the Yahoo reviews would remain.  Yahoo has not made the old reviews accessible to their clients.
A month or so ago a well-intended customer reviewed Make An Impression on yelp and gave her a 5 star review, but that one review cannot replace 7 years of 5 star reviews from Yahoo. Many businesses are being adversely affected the same way. Our advice is to not have customers review you on Yahoo and this initiative is having many businesses yell “yikes” rather than “Yahoo”.