When Google first introduced hReview around 4 years ago, we were able to put this to great use on a number of client sites that sold products / services and had a number of testimonials relating to these, which in turn had a great impact on click through rates.
One client of ours sold a niche product that had several variations, all of which received good traffic volumes. The longer tail more specific product pages listed the average score and testimonials relating to that particular product, whilst the home page showed a combined score for all the products and was optimised for the shorter tail main term.
Whilst they already ranked #1 for this main term, which at the time got around 5000 exact searches a month, the appearance of the star ratings in the SERPs saw traffic increase by 60% year on year, with the spike in traffic clearly visible from November onwards when it was first implemented!
With the stars also appearing for all the product pages, organic traffic across the whole site increased by 88%.
Recently, the stars no longer appeared on the home page, traffic dipped and we had to investigate why this was. The code had always worked fine but we still tweaked the mark up to ensure we were following the guidelines correctly. However, it just wouldn’t come back despite the rich snippets testing tool showing all the code was present and correct.
This then became apparent on other sites we had set this up on in a similar way – where the home page shows the aggregate score for its product pages.
We were aware that Google had been clamping down on rich snippet spam and wouldn’t show this in various niches or where it was clearly manipulated, but the site in question was genuine, had good authority within its niche and over 3000 reviews of varying scores.
Recently at Pubcon, Matt Cutts announced that there was to be a 15% reduction in rich snippets and authorship shown in the SERPs. The suggestion in that article that reviews would only appear for authoritative sites doesn’t quite fit, because as mentioned, this site has very good authority.
As the stars are still appearing on all the product pages on this and other sites, it looks as though part of the clamp down would also include not showing any review mark up that appears on a site’s home page. This to a degree makes sense as reviews are by design meant to be for specific products/services, although on the other hand when a search is more generic – e.g. widgets as opposed to blue widgets – it seemed fair that a site should be able to show in search their aggregate score for products / services as a whole. Indeed, a number of people who went on to buy products cited the appearance of reviews in the SERPs as influencing their decision to click through to the site.
It seems that, yet again, Google have given with one hand and taken away with the other. Since we first saw these changes, I’ve yet to see stars appear in the organic search for a home page result that wasn’t a local search term (although these stars come from Google reviews, not from site markup).
Not that I’m being cynical or anything, but this move wouldn’t be to put the focus on high volume search term results back to the ads at the top of the page, would it? Leaving sites with a drop in traffic on high volume terms that they can look to recoup by bidding on the more expensive, short tail terms?
Edit: following a discussion about this on Google+, I was directed to this article which makes for very interesting reading relating to rich snippets, their usage and what Google deem as acceptable - this gives a far clearer indication than any of guidelines on Google.com or their webmastercentral blog.