Yes, you need to build links to your site to acquire more PageRank, or Google ‘juice’ – or what we now call domain authority or trust. Google is a link-based search engine – it does not quite understand ‘good’ or ‘quality’ content – but it does understand ‘popular’ content. It can also usually identify poor, or THIN CONTENT – and it penalises your site for that – or – at least – it takes away the traffic you once had with an algorithm change. Google doesn’t like calling actions the take a ‘penalty’ – it doesn’t look good. They blame your ranking drops on their engineers getting better at identifying quality content or links, or the inverse – low-quality content and unnatural links. If they do take action your site for paid links – they call this a ‘Manual Action’ and you will get notified about it in Webmaster Tools if you sign up.
Repeat this exercise for as many topic buckets as you have. And remember, if you're having trouble coming up with relevant search terms, you can always head on over to your customer-facing colleagues -- those who are in Sales or Service -- and ask them what types of terms their prospects and customers use, or common questions they have. Those are often great starting points for keyword research.
QUOTE: “Search engine optimization is often about making small modifications to parts of your website. When viewed individually, these changes might seem like incremental improvements, but when combined with other optimizations, they could have a noticeable impact on your site’s user experience and performance in organic search results.” Google Starter Guide, 2008