They decided to redirect the URLs of the removed pages to the home page.
Here's what happened to their SEO performance:
Their home page and category pages also lost their best rankings (and organic search traffic and revenue).
Before, their home page and category pages had great rankings and generated very good SEO revenue:
It's not really surprising, but it's still interesting to see a case that confirms something lots of SEOs are probably already convinced of:
Blog articles and how-to guides often generate traffic that doesn't convert, so their value isn't always easy to show internally. It's difficult to *prove* that they help other pages rank.
Informative content pages help category pages and the home page of an e-commerce site rank better if the former contain contextual internal links pointing to the latter and if they attract links from other domains.