Even if there are some charitable explanations possible, the least courtesy would be to warn you that your comment had been removed and why. You could mark the comment as "outdated", it won't bother me (assuming something has really changed).

Here, it creates the impression that my comment was swept under the rug for some dubious reasons. And this is probably the last time I ever comment on Amazon. That does not really create a great trust in the system.

Steam does this to an extent with game reviews. Old reviews aren't removed, but they show separate ratings of "Recent Reviews" and "All Reviews", effectively reducing the potency of old reviews.

That said, video games these days can change a lot from one year to another, whereas almost all of the products on Amazon will not do so.

They actually have quite powerful tools, with a graph of reviews over time, the ability to select a custom time range from that, ..., I quite like their system.

I believe that got added to help people recognize and filter out review-bombing.

To others' point it could be in Amazons interest to have completely fake but real-looking reviews to promote their preferred products so this would then feed into that dark pattern.

Sure they can, but what about some of the products on Amazon which are mostly immutable like for example: Books.

A bad book is a bad book. Batch B of the said book is mostly a new "product" listing on Amazon with its own set of reviews and ratings.

Also if Batch C is being sold or something similar (to batches), a better idea would be (IMO) to have the product owner comment on the review, saying we have fixed this in batch 2 or batch B or something

This is OT but books can vary in quality too - specifically the paper used and the print quality. I was looking at "Physically Based Rendering" (http://a.co/bL8bjUw) after seeing the post here about rendering a scene from Moana and was disappointed to see comments about bad print quality. Hopefully this is fixed in a later print run.

>Also if Batch C is being sold or something similar (to batches), a better idea would be (IMO) to have the product owner comment on the review, saying we have fixed this in batch 2 or batch B or something

That is a good idea, but that still does not fix the aggregate data. When someone searches for "Coffee", the aggregate number of reviews is still considering that low-star review. So the "Seattle Coffee Beans" overall rating for Batch C could be a 4.5 / 5, but for all batches is a 2.5 / 5.

The easiest way to fix this is to remove old, out-of-date reviews. This should apply to positive reviews too, but I have no idea if Amazon is doing this.

Another approach is what Steam did - have a long-term rating and a "recent" rating. See "No Man's Sky" as an example [1] - a product that started poor, but improved over time. This helps prevent product brigading and gives vendors an opportunity to bounce back from negative reviews.

[1] https://store.steampowered.com/app/275850/No_Mans_Sky/

Not necessarily. The album Pinkerton by Weezer was critically panned at release but now regarded as perhaps their best album.

Tastes change. That said, you can still find those old reviews. Not so in all cases on Amazon...

Steam handles this by displaying the average from strictly recent reviews and the average over all.

For example, No Man's Sky was one of the biggest letdowns in recent gaming releases. It was later patched to be much better.

Check out the reviews here: https://store.steampowered.com/app/275850/No_Mans_Sky/

I don't know if Amazon has this feature, but I've seen sites that let the seller answer back to reviews - for cases where the seller has addressed a reviewer's feedback, they could reply and say that this has been fixed.

Or make a new listing, and in the description mention what has been fixed.

Amazon has that feature.

This happened to a Firefox extension I wote. I wrote the extension and published it to the FF extension store and got valid criticism in reviews pretty quickly. I addressed the issues and uploaded a new version of the extension. There was nothing I could do other than reply to the reviews to show I had addressed the issue. This doesn't get reflected in the overall rating. After the reviews nobody seemed to want to try the extension. Maybe it was because of the bad reviews, maybe not.

I was doing this for free, so I just shrugged my shoulders and moved on. I'm not gonna fight the system, but there is money involved I could see how someone would.

Deleting older reviews isn't the only mechanism for handling stale reviews. They could add a decay function to the weighting in average review rating and leave the contents of the original review in place, for example. New versions of products could be treated as unique products, and thus reviews could be forked.

If Batch C is different enough from Batch A that the reviews don't apply, then should it even be the same product?

In some cases, yes.

Books for example. Some print runs are terrible. So even if the content is great, terrible print quality or construction can lead to bad reviews.

Some books have numbered editions. But if the content is unchanged, should they be different products?

i think the point is that had the review been 5 stars it would still be there...

I think they could do like ebay does: reviews in the last 4 weeks, 3 months, 6 months, ...etc. Or a similar mechanism. Sometimes I am not interested to old reviews, esp. technical books, as they become very quickly outdated. Deleting them implies deleted forever, though. Such information will be always lost, while it might still apply. I would simply give it a different weight.

Aren't those time limits on reviews only for reviews of sellers, though? Does Ebay also time-limit products reviews, reviews that are divorced from a seller? Do they even host those kind of reviews?

Uh maybe you are right. It's been a long time since I've stopped using ebay.

However, I am quite sure I have seen elsewhere this feature. It's not bad. It allows to have more recent opinions about the item.

the google play store does this -- reviews left on older versions of applications will be denoted as such. the developer response to comments is also made public, so a bad review on a 1.0 release could have the dev apologizing and saying it's fixed for 1.1, with the current version being 1.1.5, and one could infer (with enough faith in the developer) that the issue is resolved.

If a batch is different enough to warrant new reviews, it's a different product and should be sold as such. Consider beer and wine. Industrially manufactured beer doesn't vary much from batch to batch, so it's sold by brand. Wine varies a lot from batch to batch, so it's sold by brand and year.

Amazon already accounts for the date of the review to some extent. If you hover over the overall rating for a product you can read:

"Amazon calculates a product’s star ratings using a machine learned model instead of a raw data average. The machine learned model takes into account factors including: the age of a review, helpfulness votes by customers and whether the reviews are from verified purchases."

The App Store does a good job with this, showing reviews for a new version while maintaining old reviews. Of course products aren’t often “versioned” so this might requiring revisiting how products are posted/managed.

Its a serious issue if Amazon does not have this feature and still deletes reviews.

Yes. Because it represents how you've chosen to run your business. You are allowed to judge the business based on their previous behavior.

You can pick a cut off date. Like only reviews in the last 18 months used to calculate score and are shown.

Only verified purchases should count as well. A lot of people review stuff just out of spite or PR reasons.