- Some review sites filter reviews from certain users
- Reviews leave the filter as those users become more active or trustworthy
There are several reasons why an old review may show up as new in our alerts. With Yelp, this happens frequently. Why?
Yelp aggressively filters (i.e. hides) reviews from new and inactive users but will ultimately “trust” those reviews should the reviewer ever become active. Therefore, it’s not uncommon for a review that has been caught in Yelp's filter for years to suddenly be published when the reviewer starts “Yelping” again years later.
A review written in 2011 could show up in your review stream tomorrow. Other review sites have their own algorithms for filtering and publishing reviews that may also lead to this behavior, but it is most common with Yelp.