If you're a regular blogger, these are probably the topics you blog about most frequently. Or perhaps they're the topics that come up the most in sales conversations. Put yourself in the shoes of your buyer personas -- what types of topics would your target audience search that you'd want your business to get found for? If you were a company like HubSpot, for example -- selling marketing software (which happens to have some awesome SEO tools ... but I digress ... you might have general topic buckets like:
When would this be useful? If your site has a blog with public commenting turned on, links within those comments could pass your reputation to pages that you may not be comfortable vouching for. Blog comment areas on pages are highly susceptible to comment spam. Nofollowing these user-added links ensures that you're not giving your page's hard-earned reputation to a spammy site.

Keyword research tells you what topics people care about and, assuming you use the right SEO tool, how popular those topics actually are among your audience. The operative term here is topics -- by researching keywords that are getting a high volume of searches per month, you can identify and sort your content into topics that you want to create content on. Then, you can use these topics to dictate which keywords you look for and target.
However, we do expect websites of large companies and organizations to put a great deal of effort into creating a good user experience on their website, including having helpful SC. For large websites, SC may be one of the primary ways that users explore the website and find MC, and a lack of helpful SC on large websites with a lot of content may be a reason for a Low rating.
Place strategic search phrases on pages. Integrate selected keywords into your website source code and existing content on designated pages. Make sure to apply a sug­gested guideline of one to three keywords/phrases per content page and add more pages to complete the list. Ensure that related words are used as a natural inclu­sion of your keywords. It helps the search engines quickly determine what the page is about. A natural approach to this works best. In the past, 100 to 300 words on a page was recommended. Many tests show that pages with 800 to 2,000 words can outperform shorter ones. In the end, the users, the marketplace, content and links will determine the popularity and ranking numbers.