Q: How can we optimize our site content for search engines but make sure it’s usable for people, too?
If you care about search engine optimization, then you most likely want users to find your site or landing page (through paid search or natural search) and take some action that’s important to you (e.g., buy something, subscribe to a newsletter, request to be contacted). It’s not enough just to be listed high up in the search results—your content needs to be optimized for people to understand and use, or they’ll click away.
For both search engines and people, it’s usually smart to put the most important information first, in page titles, headings and paragraphs (using topic sentences). Also, do your best to provide the information using the users’ vocabulary, not necessarily your own.
You also should write your link text very carefully. A link that says “click here” is relatively slow and difficult for users to process, because they have to read more to predict what they’ll get if they click on it. A “click here” link also is a wasted opportunity to tell a search engine what the link is specifically about, so your page is seen as less relevant.
Trying to trick search engine sites by inserting irrelevant keywords into your copy or endlessly repeating keywords can lead to trouble. Search engine sites may ban you, and users will be annoyed by you and click away.
Regarding the action(s) you want users to take, make sure they’re clear and prominent on the page. If you’re not sure whether buttons, links and other elements are prominent enough, then run a usability study with end-users (which is a good idea, anyway). A quicker method is to squint at your screen so it becomes blurry—do elements that stand out most on the page lead to actions you want the user to take?