One thing I’ve always recommended is to make sure that some of the most important pages on your website aren’t also the ‘thinnest’. I’m thinking of product index pages. For example, on your home page, you may have a link to ‘widgets’. On the widgets page, you have panels showing your red widgets, blue widgets and (new for 2018) beige widgets. These link through to the relevant products, but that’s it for the page. There’s nothing else of any substance. You’re telling Google that’s your most important page about ‘widgets’ in general, but it’s not exactly packed with unique information. So why not add some background?
Any SEO advisor would recommend this, but almost inevitably, it seems some people have abused it. In a recent Google ‘Webmaster Hangout’, a case was discussed of added content having a negative impact. The Hobo website reported Google’s response to be that some sites have taken a category page that’s pretty good and stuffed text on the bottom only roughly related to that content, but making it bigger than the Wikipedia page on that topic. The search engine’s algorithms equate this to frowned-upon ‘keyword stuffing’ and are much more cautious in their rating of the page.
So just be sensible. A few paragraphs of genuinely helpful background information to make a category page more substantial can go a long way. Many screens full of waffle will push you down the other side of the hill again.